Research advances of un-symmetric constitutive equation of anisotropic fluid, influence of un-symmetric stress tensor on material functions, vibrational shear flow of the fluid with small amplitudes and rheology of anisotropic suspension were reported. A new concept of simple anisotropic fluid was introduced. On the basis of anisotropic principle, the simple fluid stress behaviour was described by velocity gradient tensor F and spin tensor W instead of velocity gradient tensor D in the classic Leslie-Ericksen continuum theory. Two relaxation times analyzing rheological nature of the fluid and using tensor analysis a general form of the constitutive equation of co-rotational type was introduced. More general model LCP-H for the fluid was developed. The unsymmetry of the shear stress was predicted by the present continuum theory for anisotropic viscoelastic fluid-LC polymer liquids. The influence of the relaxation times on material functions was specially studied. It is important to study the unsteady vibrational rotating flow with small amplitudes, as it is a best way to obtain knowledge of elasticity of the LC polymer, i.e. dynamic viscoelasticity. For the shear-unsymmetric stresses, two shear stresses were obtained thus two complex viscosities and two complex shear modulus (i.e. first and second one) were introduced by the constitutive equation which was defined by rotating shear rate introduced by author. For the two stability problems of fluid, such as stability of hydrodynamic flow and orientational motion, were discussed. The results show that the polymer suspension systems exhibit anisotropic character. The PNC systems can exhibit significant shear-thinning effects. For more concentrated polymer nano-suspensions, the first normal stress difference change from positive to negative, which is similar to LC polymer behavior.

The hear transfer mechanism and the constitutive models for energy boundary layer in power law fluids were investigated. Two energy transfer constitutive equations models were proposed based on the assumption of similarity of velocity field momentum diffusion and temperature field heat transfer. The governing systems of partial different equations were transformed into ordinary differential equations respectively by using the similarity transformation group. One model was assumed that Prandtl number is a constant, and the other model was assumed that viscosity diffusion is analogous to thermal diffusion. The solutions were presented analytically and numerically by using the Runge-Kutta formulas and shooting technique and the associated transfer characteristics were discussed.

The average stretching direction, local rotation angular, and stretching ratio parameters of molecular trains were used to express the rheology deformation. Based on this micro geometrical deformation, the macro deformation of medium was expressed. Then, using intrinsic elasticity concept, the stress—strain relation was obtained. In this theoretic formulation, the response functions of extension ratio and rotation angular were used to express the rheology feature of medium. For medium composed by incompressible molecular trains, the local rotation angular divides rheology deformation into three kinds: viscoelastic deformation or elasticity enhancement, viscoplastic deformation or elasticity degenerate and constant elasticity range. These results explain the experimental features of rheology deformation well.

A uniaxial viscoelastoplastic model that can describe whole creep behaviors of asphalt sand at different temperatures was presented. The model was composed of three submodels in series, which describe elastoplastic, viscoelastic and viscoplastic characteristics respectively. The constitutive equation was established for uniaxial loading condition, and the creep representation was also obtained. The constitutive parameters were determined by uniaxial compression tests under controlled-stress of 0.1 MPa with five different test temperatures of 20, 40, 45, 50 and 60 °C. Expressions of the model parameters in terms of temperatures were also given. The model gave prediction at various temperatures consistent with the experimental results, and can reflect the total deformation characterization of asphalt sands.

The dynamic analysis of semi-flexible polymers, such as DNA molecules, is an important multiscale problem with a wide range of applications in science and bioengineering. In this contribution, a dumbbell model with internal viscosity was studied in steady shear flows of polymeric fluid. The tensors with moments other than second moment were approximated in the terms of second moment tensor. Then, the nonlinear algebraic equation of the second moment conformation tensor was calculated in closed form. Finally, substituting the resulting conformation tensor into the Kramers equation of Hookean spring force, the constitutive equations were obtained. The shear material properties were discussed for different internal viscosities and compared with the results of Brownian dynamics simulation.

To completely understand the rate-dependent stress-strain behavior of the porous nanocrystalline materials, it is necessary to formulate a constitutive model that can reflect the complicated experimentally observed stress-strain relations of nanocrystalline materials. The nanocrystalline materials consisting grain interior and grain boundary are considered as viscoplastic and porous materials for the reasons that their mechanical deformation is commonly governed by both dislocation glide and diffusion, and pores commonly exist in the nanocrystalline materials. A constitutive law of the unified theory reflecting the stress-strain relations was established and verified by experimental data of bulk nanocrystalline Ni prepared by hydrogen direct current arc plasma evaporation method and hot compression. The effect of the evolution of porosity on stress-strain relations was taken into account to make that the predicted results can keep good agreements with the corresponding experimental results.

To determine structure and parameters of a rheological constitutive model for rocks, a new method based on differential evolution (DE) algorithm combined with FLAC^3D (a numerical code for geotechnical engineering) was proposed for identification of the global optimum coupled of model structure and its parameters. At first, stochastic coupled mode was initialized, the difference in displacement between the numerical value and in-situ measurements was regarded as fitness value to evaluate quality of the coupled mode. Then the coupled-mode was updated continually using DE rule until the optimal parameters were found. Thus, coupled-mode was identified adaptively during back analysis process. The results of applications to Jinping tunnels in China show that the method is feasible and efficient for identifying the coupled-mode of constitutive structure and its parameters. The method overcomes the limitation of the traditional method and improves significantly precision and speed of displacement back analysis process.

Using the constitutive equation of co-rotational derivative type for anisotropic viscoelastic fluid-liquid crystalline (LC), polymer liquids was developed. Two relaxation times are introduced in the equation: λ_n represents relaxation of the normal-symmetric stress components; λ_s represents relaxation of the shear-unsymmetric stress components. A vibrational rotating flow in gap between cylinders with small amplitudes is studied for the anisotropic viscoelastic fluid-liquid crystalline polymer. The time-dependent constitutive equation are linearized with respect to parameter of small amplitude. For the normal-symmetric part of stress tensor analytical expression of the shear stress is obtained by the constitutive equation. The complex viscosity, complex shear modulus, dynamic and imaginary viscosities, storage modulus and loss modulus are obtained for the normal-symmetric stress case which are defined by the common shear rate. For the shear-unsymmetric stress part, two shear stresses are obtained thus two complex viscosities and two complex shear modulus (i.e. first and second one) are given by the constitutive equation which are defined by rotating shear rate introduced by author. The dynamic and imaginary viscosities, storage modulus and loss modulus are given for each complex viscosities and complex shear modulus. Using the constituive equation the rotating flow with small amplitudes in gap between two coaxial cylinders is studied.

The formation and evolution laws of the defect temperature field, heat dissipation in the process of defect evolution were studied. On the basis, the formation and evolution laws of the defect temperature field were investigated, the interaction among defects in the process of defect evolution was carried out. The numerical simulation of the temperature field of ABS was made. The results show that the process of defect evolution is one of energy dissipation, in which the defect temperature field forms due to that its heat dissipation possesses fractal property and its fractal dimension not only relates to the interaction among the defects, but also is the function of time, this incarnates the efficiency of coordinated actions of striding over the different gradations in the process of defect evolution and among gradations. The increase of the local temperature with the increase of deformation-induced heating effect in ABS is obvious. Moreover, the shape of plastic zone and inner heat source density function has big effect on the temperature field.

Plastic variational principles are foundation to solve the boundary-value problems of plastic mechanics with the variational method (or energy method) and finite element method. The most convenient way of establishing different kinds of variational principles is to set up the extreme principle related to the studied problem. Based on a general new extreme principle-the Least work consumption principle, the variational principles of the rigid-plastic and rigid-viscoplastic material were derived. In comparison with existing methods, the method in this paper is more clear and direct, and the physical meaning is clear-cut. This method can offer a new way for establishing other kinds of variational principles.

The basic factors relating to the rheological stress in the constitutive equations were introduced. Carbon constructional quality steels were regarded as a kind of elastic-viscoplastic materials under high temperature and the elastic-viscoplastic constitutive models were summarized. A series of tension experiments under the same temperature and different strain rates, and the same strain rate and different temperatures were done on 20 steel, 35 steel and 45 steel. 52 groups of rheological stress—strain curves were obtained. The experimental results were analyzed theoretically. The rheological stress constitutive models of carbon steels were built combining the strong points of the Perzyna model and Johnson-Cook model. Comparing the calculation results conducted from the model with the experiment results, the results proves that the model can reflect the temperature effect and strain rate effect of carbon constructional quality steels better.

Application research of neural networks to geotechnical engineering has become a hotspot nowadays. General model may not reach the predicting precision in practical application due to different characteristics in different fields. In allusion to this, an elasto-plastic constitutive model based on clustering radial basis function neural network(BC-RBFNN) was proposed for moderate sandy clay according to its properties. Firstly, knowledge base was established on triaxial compression testing data; then the model was trained, learned and emulated using knowledge base; finally, predicting results of the BC-RBFNN model were compared and analyzed with those of other intelligent model. The results show that the BC-RBFNN model can alter the training and learning velocity and improve the predicting precision, which provides possibility for engineering practice on demanding high precision.

Mathematical model of filling disk-shaped mold cavity in steady state was studied. And the mathematical model under vibration field was developed from the model in steady state. According to the model of filling disk-shaped mold cavity in steady state, the filling time, the distribution of velocity field and the pressure field were obtained. The analysis results from rheological analytic model were compared with the numerical simulation results using Moldflow software in the powder injection molding filling process. Through the comparison, it is found that it is unreasonable to neglect the influence of temperature when calculated the pressure changing with the time at the cavity gate, while it can be neglected in other situations such as calculating the distribution of the velocity fields. This provides a theoretical reference for the establishment of correct model both in steady state and under vibration force field in the future.

Vibration equations of time-varying system are transformed to the form which is suitable to precise integration algorithm. Precision analysis and computation efficiency of new algorithm are implemented. The following conclusions can be got. Choosing matrixes M, G and K is certainly flexible. We can place left side of nonlinear terms of vibration equations of time-varying system into right side of equations in precise integration algorithms. The key of transformation from vibration equations of time-varying system to first order differential equations is to form matrix H, which should be assured to be nonsingular. With suitable disposal, precision and computation efficiency of precise integration algorithms are greatly larger than those of general methods.

In order to get the formulae for calculating the equivalent frame width coefficient of reinforced concrete hollow slab-column structures with edge beam, the finite element structural program was used in the elastic analysis of reinforced concrete hollow slab-column structure with different dimensions to study internal relationship between effective beam width and the frame dimensions. In addition, the formulas for calculating the increasing coefficient of edge beam were also obtained.

The experimental observations about remarkable influence of the substrates on the isothermal crystallization rate of a high density polyethylene(HDPE) were presented. Two methods were used to characterize the crystallization rate: the change of turbidity of the HDPE specimen and the changes of the complex viscosity and storage modulus measured by a rotational rheometer, which gave consistent results showing that the isothermal crystallization rate decreased in sequence as the specimen contacted with aluminum, brass and stainless steel plates, respectively. As to the dominant influence factor, the chemical composition of the substrates can be excluded via insulating the plate by an aluminum foil. Instead, we propose the plate’s ability of removing the latent heat of crystallization from the specimen. Rheological measurement is sensitive to the crystallization process. The colloid like model proposed by BOUTAHAR et al for the crystallization of HDPE gives reasonable predictions of the crystallized fraction from the measured storage modulus.

The relationship between rheological properties and morphology of immiscible polystyrene(PS)/poly(methyl methacrylate)(PMMA) blends was studied. The blends were prepared using a twin screw extruder. A single screw extruder equipped with a slit die was used to perform shear flow measurements of PS/PMMA blends. Morphological examinations were conducted on the cryogenically fractured and extracted samples by scanning electron microscopy. The results show that the melt viscosity of PS/PMMA blend decreases with increasing shear stress, which is attributed to not only the disentanglement of macromolecules but also the reduction in the domain size and the resultant increase of the interfacial area. The power-law index of the blend melt is lower than any of its component melt, suggesting that deformation and breakup of the dispersed phase increase the dependence of the melt viscosity on the shear stress. The blend whose domain size decreases at a faster rate with increasing shear stress, exhibits a strong shear rate dependence on the melt viscosity. The comparison of the morphologies of samples before and after the slit section of the die indicates that the morphology of the blend has a quick response to shear flow, the coalescence of the dispersed drops is predominant for blends at low shear rates.

A novel polyamide 6/silica nanocomposite containing epoxy resins (EPA6N) was prepared via in situ polymerization using tetraethoxysilane (TEOS) as the precursor of silica. The dynamic rheological properties of pure PA6 and EPA6N at temperatures of 225 and 235 °C were investigated. The results of transmission electron microscopy (TEM) and atomic force microscopy (AFM) indicate that the silica particles are well dispersed in the polyamide 6 matrix on about 30 nm in diameter, which demonstrates that this method can effectively avoid agglomeration of the inorganic particles. The rheological results suggest that pure PA6 shows Newtonian behavior. However, the novel EPA6N exhibits a solid-like rheological behavior, which is due to the small size, large surface of silica particles and the stronger polyamide 6-silica chemical bond formed through the reactions of epoxy resins with end groups of PA6 molecular chains. The EPA6N also exhibits higher melt viscosity, storage modulus and loss modulus than those of pure PA6.

The effect of salt solutions (NaCl, Na₂SO₄ and CaCl₂) on the conformational properties of partially hydrolyzed polyacrylamide (HPAM) was investigated by using static laser light scattering (SLLS). The special interaction between CaCl₂ solution and HPAM was also researched. Experimental results show that the chain structure of HPAM is interrelated with the charge density, the kind and the concentration of salt solutions. The mean-square radius of gyration (R_z) and the second virial coefficient (A₂) of HPAM decrease with increasing concentration of salt solutions, and the salt effect tends towards the maximum when the concentration of salt solution is increased to some amount.

For waterflooding reservoir, oil trapped in pore’s dead ends is hardly flushed out, and usually becomes one typical type of residual oil. The microscopic displacement characteristics of polymer solution with varied viscoelastic property were studied by numerical and experimental method. According to main pore structure characteristics and rheological property of polymer solution through porous media, displacement models for residual oil trapped in dead ends were proposed, and upper-convected Maxwell rheological model was used as polymer solution’s constitutive equation. The flow and stress field was given and displacement characteristic was quantified by introducing a parameter of micro swept coefficient. The calculated and experimental results show that micro swept coefficient rises with the increase of viscoelasticity; for greater viscoelasticity of polymer solution, vortices in the dead end have greater swept volume and displacing force on oil, and consequently entraining the swept oil in time. In addition, micro swept coefficient in dead end is function of the inclination angle (θ) between pore and dead end. The smaller of θ and 180-θ, the flow field of viscoelastic fluid is developed in dead ends more deeply, resulting in more contact with oil and larger swept coefficient.

Rheological properties of microemulsions (MEs) and their printability in three dimensional printing (3DP) systems were investigated. A series of MEs with different contents of oil phase were prepared using sonication method with ibuprofen as model drug and soybean lecithin as emulfier. Stationary and transient rheological properties of MEs were investigated by ARES-SRF using concentric cylinders measuring systems. 3DP systems with piezoelectric drop-on-demand print heads were employed to test the printability of the MEs. Results demonstrate that the apparent viscosity and dynamic linear viscoelastic regions of the MEs are the most important parameters for continuous and stable printing of MEs by 3DP. The incorporation of drug in the MEs has little influence on the MEs’ stationary rheological behaviors and dynamic viscoelasticity, but the concentration of oil phase has a strong influence on them. The rheological property of binder liquids has a close relationship with their printability in 3DP system.

The rheological properties of salt-tolerant partially hydrolyzed polyacrylamide (HPAM)solutions with molecular of 2.5×10⁷ g/mol at different concentrations were measured in steady-state shear flow mode by Haake Rheostress 150 rheometer. Three constitutive equations (Oldroyd four constant model, Guesekus model and FENE-P model) were used for describing the apparent viscosity and first normal stress difference. The apparent viscosity of salt-tolerant HPAM solutions appears a first Newtonian zone when the shear rate is approximately lower than 0.2 s⁻¹. At high shear rate, the HPAM solutions show shear-thinning and elasticity. The results show that the FENE-P model has the best agreement between theoretical and experimental data within the available shear rate range. The material parameters are useful for numerical analysis of polymer solution flow fields.

Thermo-responsive multiblock polycarbonates were facilely synthesized by covalently binding poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG) blocks, using triphosgene as coupling agent and pyridine as catalyst. The aqueous solutions of thermo-responsive polycarbonates were investigated by rheological measurements. Steady-state shear measurements reveal that the polycarbonate solutions exhibit shear-thinning behavior and the hydrophilic content has a pronounced effect on the flow behavior of the polycarbonates aqueous solutions. The shear viscosity decreases with increasing poly(ethylene oxide) (PEO) composition. The increase of viscosity with increasing concentration is probably attributed to the formation of stronger network owing to interchain entanglement of PEO block at higher concentration. When the flow curves are fitted to the power law model, flow index is obtained to be less than 1, as exhibiting typical pesudoplastic fluid. The viscoelastic properties of the system also show close dependence on the composition of polycarbonates. Temperature sweep confirms that the multiblock polycarbonates exhibit thermo-responsive properties. For 7% aqueous solution of polycarbonate with composition ratio of EO to PO of 1/1, the sol-gel transition occurs at 37 °C, which makes the system suitable as an injectable drug delivery system.

Poly(acrylamide-co-sodium acrylate) (PAM/AA-Na) and poly(acrylamide-co-sodium vinylsulfonate) (PAM/VSS-Na) were prepared by inverse emulsion polymerization. The effects of CaCl₂ on PAM/VSS-Na or PAM/VSS-Na aqueous solutions were investigated by steady-flow experiments at 25, 40, 55 and 70 °. The results show that the apparent viscosities of both solutions decrease with addition of CaCl₂ or increase of temperature and shear rates. PAM/VSS-Na solution has better performance on the salt tolerance, shear endurance and temperature resistance due to containing sulfonic group in the molecules. Ca²⁺ concentration can affect the viscous activation energy of both solutions and the reason may be that these interactions between Ca²⁺ and also copolymer molecules are related to temperature and competitive in solution. These results may offer the basic data for searching the flooding systems with the ability of temperature resistance, salt tolerance and shear endurance for tertiary oil recovery.

The fatigue properties of asphalts were investigated after various laboratory simulation ageing tests and outdoor natural exposure ultraviolet radiation ageing, by dynamic shear rheometer (DSR) time sweep fatigue test in constant strain model and a new type of specimen which was introduced to avoid the problem of adhesion failure between rotor and asphalt binder. The results show that outdoor natural exposure ageing (NEA) causes the decrease of retained fatigue life distinctly, and photodegradation caused by outdoor NEA of 1 250 μm thin films asphalt for three months, is found to be severer than pressure ageing vessel (PAV) with respects to retained fatigue life. The effect of photodegradation increases as the time of outdoor NEA increases. DSR time sweep fatigue test in constant strain indicates that the aged styrene-butadiene-styrene (SBS) modified asphalt still displays better fatigue properties than the corresponding base asphalt after ageing.

The effect of sulfide on HPAM solution viscosity was studied using BROOKFIELD DV-II viscometer, and the interaction mechanism was discussed. The HPAM solution viscosity was investigated through fully reducing sulfide by the addition of hydrogen peroxide oxidation, and the mechanism of increasing polymer viscosity was investigated. The experimental results also show that there is a critical concentration of 15 mg/L. Below it, the loss rate of HPAM solution viscosity increases more rapidly, but becomes slowly above the critical concentration. A theoretical guidance for oilfields to prepare polymer solution using sewage-water by eliminating sulfide, and it is also importance to prepare polymer solution using sewage-water and save fresh water.

Rheological properties of the virgin bitumen and TPS modified bitumen binders with several percentages of TPS additives were studied. All TPS modified bituminous binders were prepared on a laboratory scale. Dynamic shear rheometer (DSR) strain sweep test was made to measure the linear viscoelasticity areas of various bitumen binders at −20–70 °C, then temperature sweep test and frequency sweep test were made in the linear viscoelasticity areas. Complex modulus master curves were drawn to analyze and compare various bitumen binders’ rheological properties. Based on the test results, the ideal percentage of TPS additive was brought forward. The results show that TPS modified bitumen binders have more excellent properties at high, medium and low temperatures compared with original bitumen. The dosages of TPS additive are vital to their properties.

Dynamic viscoelastic properties of polyacrylonitrile(PAN)/DMSO/H₂O solutions with different H₂O contents were studied as a function of temperature. These PAN solutions gradually became gel with decreasing temperature. The sol-gel transition took place at a critical gel temperature, at which the scaling law of G′(ω)∼G″(ω)∝ωⁿ held, allowing an accurate determination of the critical gel temperature by means of the frequency independence of the loss tangent. The gel point of PAN solutions increases with increasing H₂O content. The scaling exponent n (=0.86) at the gel point is confirmed to be universal for PAN gels, which is independent of temperature, suggesting the similarity of the fractal structure in the critical PAN gels.

The capability of hydrophobic association polymer (HAPAM) to displace oil is different from that of hydrolyzed polyacrylamide (HPAM) because they have different rheological properties. The viscoelasticity of five polymers was measured using Physica MCR301 rheometer and was compared. The five polymers include three HAPAMs with relative molecular mass of 1 248×10⁴ (Type I), 750×10⁴ (Type II), and 571×10⁴ (Type III) separately and two HPAMs with relative molecular mass of 1 200×10⁴ and 3 800×10⁴ respectively. The experiment results indicate that the viscoelasticity of HAPAM is better than that of HPAM. The storage modulus G′ and the loss modulus G″ for HAPAM solutions are also larger than those for HPAM. Comparing the rheological curves of different HAPAM types, it is found that the viscosity of type II and type III is almost same at different shear rates while the viscosity of type I is the lower than that of Types II and III. The storage modulus G′ and the loss modulus G″ for three types of HAPAM were measured in low oscillation frequency range, and the results show that G′ is greater than G″ for all three different types of HAPAM, but their loss modulus is almost same, and the G′ is in the order of type II>type III>type I. In addition, the G′ and G″ increase with aging time for all three HAPAM solutions were stayed at different days. The viscoelasticity of type I reaches the highest value when aging time is 9 d at 45 °C, but it is 7 d for type II and type III. The different viscoelasticity properties can be attributed to self-organization supermolecule networks which is formed by hydrophobic association of HAPAM molecular and molecular chain entanglement.

Modern processing technology is calling the scientific understanding of dynamic processes, where the science of complex fluids plays a central role. We summarize our recent efforts using the generic approaches of multi-scale physics of complex fluids on apparently irrelevant processes, i.e. the mixing of polymer blends, the processing of thermoplastic(TP) toughened thermosetting(TS) composites using phase separation of TP in TS, as well as the enhanced oil recovery using polymer soft gel. It is emphasized that the thorough physical understanding in multi-scales of time and space through the joint efforts of experiment and theory in each scale is the key issue for the modeling of various processes.

High temperature rheological properties of fiber modified asphalt binders and impact of the type and content on such properties were studied. Three types of fiber, including polyester (PET), polyacrylonitrile (PAN) and cellulose (CEL), a control content (0%) and four levels of fiber content (2%, 4%, 6% and 8% by total asphalt binder mass) were used with asphalt binders. The high temperature rheological properties, consisting of complex modulus (G*) and phase angle δ, were measured using SHRP’s dynamic shear rheometer (DSR) between 46–82 °C. Experimental results indicate that the changes of G* and tan δ of fiber modified asphalt binders with the increase of test temperature tend to slow down, and the temperature susceptibility is improved obviously compared to that of original asphalt binder. Fiber modification results in the increase of rutting parameter (G*/sin δ) at high temperatures, the decrease of temperature susceptibility, and further improved high temperature performance of asphalt binder. An excellent correlation exhibits between fiber content and high temperature performance of asphalt binder. Moreover, fiber type also has different influences on the improvement of G*/sin δ, G*/sin δ of PET and PAN fiber asphalt binders are both higher than that of CEL fiber, but G*/sin δ of CEL fiber is still higher than that of original asphalt. However, there is a critical fiber content when fibers start to interact with each other. Therefore, based on the critical fiber content and economic consideration, the optimum fiber contents for various fiber-modified asphalt binders are obtained.

Air-bubble generator is the key part of the self-inspiration type swirl flotation machines, whose flow field structure has a great effect on flotation. The multiphase volume of fluid (VOF), standard k-ɛ turbulent model and the SIMPLE method were chosen to simulate the present model; the first order upwind difference scheme was utilized to perform a discrete solution for momentum equation. The distributing law of the velocity, pressure, turbulent kinetic energy of every section along the flow direction of air-bubble generator was analyzed. The results indicate that the bubbles are heavily broken up in the middle cross section of throat sect and the entrance of diffuser sect along the flow direction, and the turbulent kinetic energy of diffuser sect is larger than the entrance of throat sect and mixing chamber.

The objective of this work is to verify the rheological behavior of irradiated [Me₃NC₂H₄OH]⁺[Zn₂Cl₅]⁻ and [Me₃NC₂H₄OH]⁺[Zn₃Cl₇]⁻ ionic liquids in comparison to the unirradiated ones, the viscosities were measured by a strain-control experiment under different irradiation doses’ samples(0, 10, 20, 50, 100 kGy) at different shear rates and temperatures. The curves of shear stress against shear rate present that the viscosity of ionic liquid is insensitive to shear rate; the viscosity of ionic liquids decreases with increasing temperature, and can be fitted by Arrhenius equation very well. Gamma radiation causes a decrease of viscosity of [Me₃NC₂H₄OH]⁺[Zn₃Cl₇]⁻ by greater than 10%, but it does not impair the viscosity of [Me₃NC₂H₄OH]⁺[Zn₂Cl₅]⁻ (within the experimental error) except 20 kGy irradiated sample. The results show that the radiation stability of [Me₃NC₂H₄OH]⁺[Zn₂Cl₅]⁻ is higher than that of [Me₃NC₂H₄OH]⁺[Zn₃Cl₇]⁻.

A simple one-dimensional planar model for ejection was set up based on experiments. And numerical simulation was performed on this model with particle trajectory model method. An Eulerian finite volume method was conducted to resolve gas field. And Lagrangian method was imposed to track each particle. The interaction between gas and particles was responded as source terms in governing equations which were induced by forces. The effects of total spraying mass, particle size and other factors on the mixture of particles and gas were investigated. The spatial distributions of particle mass and velocity at different time were presented. The result shows that the numerical results are qualitatively consistent to those of experiments.

A three-dimensional (3D) lattice model for predicting the rheological behavior of asphalt mixtures was presented. In this model asphalt mixtures were described as a two-phase composite material consisting of asphalt sand and coarse aggregates distributed randomly. Asphalt sand was regarded as a viscoelastic material and aggregates as an elastic material. The rheological response of asphalt mixture subjected to different constant stresses was simulated. The calibrated overall creep strain shows a good approximation to experimental results.

Surface treatment of glass bead (GB) was carried out by using γ-glycidoxypropyltrimethoxy silane (GPTES) and γ-methacryloxypropyltrimethoxy silane (MPTMS) as coupling agents, respectively. The steady viscosity and yield stress of the GB/hydroxyl terminated polybutadiene (HTPB) suspensions were determined by Brookfield R/S rheometer. The effect of surface treatment on the viscosity and yield stress of GB/HTPB suspension was investigated. The results indicate that the viscosity of the pristine GB/HTPB suspension increases with increasing GB, and the relationship between its viscosity and volume fraction of GB depends on the shear rate. The modification of GB by MPTMS changes the viscosity of the MPTMS@GB/HTPB suspension, and its viscosity is the minimum at the MPTMS dosage of 0.3 g per 1 g GB. Additionally, the modification of GB by MPTMS increases the yield stress of the GB/HTPB suspension, and its yield stress is the maximum at the MPTMS dosage of 0.1 g per 1 g GB. The GPTES modified GB/HTPB suspension behaves lower viscosity and weaker shear thinning than the MPTMS modified GB/HTPB suspension within the range of experimental shear rate.

High-viscosity dispersing system is formed by dispersing the solid particles in the high-viscosity continuous medium. It is very easy to form the three-dimensional network structure for solid particles in the system and the rheology behavior becomes complicated. The apparent viscosity of this dispersing system always has the connection with the volume ratio and the shear rate. In order to discuss the rheology behavior and put up the viscosity model, the suspension of silicon dioxide and silicon oil were prepared. Through testing the viscosity, the solid concentration and the shear rate, the effects of the ratio and the shear rate on viscosity was analyzed, the model of the high-viscosity dispersing system was designed and the model with the printing ink were validated. The experiment results show that the model is applicable to the high-viscosity dispersing systems.

Organic montmorillonite (OMMT) modified bitumen nanocomposites was prepared by melt blending. The effects of thin-film oven test(TFOT) and pressure ageing vessel(PAV) on rheological properties of pristine bitumen and OMMT modified bitumen were investigated by dynamic shear rheometer (DSR). The results show that complex modulus (G*) increases, phase angle (δ) decreases and rutting factor (G*/sin δ) is enhanced for the pristine bitumen after TFOT, whereas G*, δ and G*/sin δ of OMMT modified bitumen have a little change before and after TFOT. Besides, the pristine bitumen exhibits a large increase of G* and a great decrease of δ after PAV aging. However, the changes in G* and δ of OMMT modified bitumen are small before and after PAV. Compared with the pristine bitumen, OMMT modified bitumen presents a lower fatigue factor (G*sin δ) after PAV. As a consequence, resistance to thermal-oxidative aging of bitumen is remarkably improved due to the introduction of OMMT.

Different composites of organomodified montmorillonite (OMMT)/bitumen were prepared by melt blending with hexadecyl dimethyl benzyl ammonium modified montmorillonite (HBM) and double octadecyl dimethyl ammonium modified montmorillonite (DOM). The structures of two kinds of montmorillonite modified bitumen were characterized by X-ray diffraction (XRD). The effects of different montmorillonites on the dynamic rheological properties of the modified bitumens were investigated by dynamic shear rheometer (DSR). The XRD results show that DOM modified bitumen forms an intercalated structure, whereas the HBM modified bitumen forms an exfoliated structure. DSR results indicate that OMMT modified bitumens exhibit higher complex modulus, lower phase angle than pristine bitumen, which means that the resistance to rutting at high temperatures of pristine bitumen is improved due to the introduction of OMMT. Compared with DOM modified bitumen, HBM modified bitumen shows better rutting resistance, which is contributed to the formation of exfoliated structure in HBM modified bitumen.

The viscoelastic micelle systems formed by novel anionic-nonionic dimeric surfactant and conventional cationic surfactant cetyltrimethylammonium(1631) were studied. The viscoelasticity, thixotropy, flow curves and constitutive equation for the novel viscoelastic micelle systems were investigated. The results show that the micelle systems possess viscoelasticity, thixotropy, and shear thinning property. Some micelle systems possess hysteresis loops showing both viscoelasticity and thixotropy. It is proved that the flow curves are characterized by the co-rotational Jeffreys constitutive equation correctly.

The internal turbulent flow in conical diffuser is a very complicated adverse pressure gradient flow. DLR k-ɛ turbulence model was adopted to study it. The every terms of the Laplace operator in DLR k-ɛ turbulence model and pressure Poisson equation were discretized by upwind difference scheme. A new full implicit difference scheme of 5-point was constructed by using finite volume method and finite difference method. A large sparse matrix with five diagonals was formed and was stored by three arrays of one dimension in a compressed mode. General iterative methods do not work wel1 with large sparse matrix. With algebraic multigrid method(AMG), linear algebraic system of equations was solved and the precision was set at 10⁻⁶. The computation results were compared with the experimental results. The results show that the computation results have a good agreement with the experiment data. The precision of computational results and numerical simulation efficiency are greatly improved.

The element-free method is a new numerical technique presented in recent years. It uses the moving least square(MLS) approximation as its shape function, and it is determined by the basic function and weight function. The weight function is the mainly determining factor, so it greatly affects the accuracy of the computational results. The element-free Galerkin method(EFGM) was applied for the solution to plastic large deformation. The simulation of metal rheological forming was successfully done by programming and its results were visualized by using the plotting and data analyses software Tecplot. Then plastic strain under different stages during rheological forming and the three principal stresses at the last deformation were obtained. The example shows the feasibility of EFGM used for metal rheological forming and provides a new method for numerical simulation of rheological forming of complex parts.

The non-linear equations of strings under a concentrated load were derived. The formulae of the linear frequency and the governing equation of the primary resonance were obtained by Galerkin and Multiple-dimensioned method. The reason of the loss of load in practical engineering was addressed. The bifurcation graphics and the relationship graphics of bifurcate point with concentrated load and the span length of the cable were obtained by calculating example. The results show that formula of the linear frequency of the suspended cable is different from that of the string.

Argon ion laser was used as the induced light source and ethane (C₂H₄) was selected as the precursor gas, in the variety ranges of laser power from 0.5 W to 4.5 W and the pressure of the precursor gas from 225×133.3 Pa to 680×133.3 Pa, the experiments of laser induced chemical vapor deposition were proceeded for fabrication of micro carbon pillar. In the experiments, the influences of power of laser and pressure of work gas on the diameter and length of micro carbon pillar were investigated, the variety on averaged growth rate of carbon pillar with the laser irradiation time and moving speed of focus was discussed. Based on experiment data, the micro carbon pillar with an aspect ratio of over 500 was built through the method of moving the focus.

The mechanical behavior of EPS (Expanded polystyrene) with three densities at room temperature and under tension loading was studied. The results show that EPS material is characterized by brittle behavior in the tension tests, and tensile properties of EPS increase with the increase of density. Volume fraction has no a significant effect on the modulus of these foams. The tensile creep strain increases with stress for EPS with same density, indicating that the creep behavior is of the stress dependency. And the creep behavior of EPS exhibits density dependency, which the creep strain decreases with densities for a fixed stress value. Moreover the creep behavior under the constant tension load is well in coincidence with the three-parameter solid model.

Creep tests under at a certain temperature and different stress levels were performed on two carbon constructional quality steels at a certain stress level and different temperatures, and their creep curves at high temperature were obtained based on analyzing the testing data. Taking 45 steel at a certain temperature and stress as the example, the integral creep constitutive equation and the differential stress-strain constitutive relationship were established based on the relevant rheological model, and the integral core function was also obtained. Simultaneously, the viscous coefficients denoting the viscous behavior in visco-plastic constitutive equation were determined by taking use of the creep testing data. Then the viscous coefficients of three carbon steels (20 steel, 35 steel and 45 steel) were compared and analyzed. The results show that the viscosity is different due to different materials at the same temperature and stress.

The adhesion coefficient of automobile tire and road surface was analyzed and the formula about it was derived. Some suggestions about highway construction, driving safety of the drivers and the judgment of the traffic accidents were presented. The results show that the adhesion coefficient is a function with the extreme value. If there is atmospheric pressure in the tire, the load of the vehicle and the degree of the coarse on the road surface is not selected properly, it will reach the least and affect the safety of the running automobile.

The meshless method is a new numerical technology presented in recent years. It uses the moving least square (MLS) approximation as its shape function, and it is determined by the basic function and weight function. The weight function is the mainly determining factor, so it greatly affects the accuracy of the computational results. The process of cylinder compression was analyzed by using rigid-plastic meshless variational principle and programming reproducing kernel partial method (RKPM), the influence of node number, weight functions and size factor on the solution was discussed and the suitable range of size factor was obtained. Compared with the finite element method (FEM), the feasibility and validity of the method were verified, which proves a good supplement of FEM in this field and provides a good guidance for the application of meshless in actual engineering.

Through adding different additional water use, the compressive strength, splitting tensile strength and fluidity of recycled concrete of three aggregate combination forms were studied by experiment respectively. The experimental results show that with the increase of adding additional water use, the compressive strength and splitting tensile strength of recycled coarse aggregate concrete decrease, but that of recycled fine aggregate concrete and recycled all aggregate concrete increase firstly then decrease. When additional water use is added more 15% or 20% than that of basic ordinary concrete, the recycled coarse aggregate concrete and fine one can get pretty good fluidity. When it is added more 30%, the recycled all aggregate concrete has fluidity that is just satisfied.

The operating principle of measuring rheological properties of magnetorheological(MR) fluid was expounded by means of a new rheometer with double driving discs rotating at the same speed in the opposite directions. The constitutive equation of MR fluid was established with theoretical analysis from experimental data. The conventional power spectrum approach was unable to detect the existence of quadratic phase coupling for dynamic rheological measurement. Bispectrum analysis is emerging as a new powerful technique in signal processing, which can describe nonlinear coupling, restrain Gaussian noise and reserve phase component. An autoregressive(AR) model of the third order cumulant, the bispectra and bispectral contours were utilized for analyzing the dynamic characteristics of the MR rheometer by merely using the sampled output torque signals when a zero mean non-Gaussian white noise interferes with the rotary disc system. The measurement and analysis process based on virtual instruments were automatically controlled by computer in this paper. The experimental and theoretical results show that rheological properties and dynamic characteristics of MR fluid can be measured with this double disc rheometer.

The measurement system is the main equipment of the project. Based on the characteristic of experiment system, a sensor array is designed, and used to continually acquire the global magnetic field. A scientific scheme is developed to get the signal processing and temperature compensation for nondirective weak magnetic field. The software of sampling control system is given, which is complied using C language in Labwindows/CVI. Taking computer as main engine, the system can acquire the nondirective weak magnetic field automatically and continuously use the sensor array, the change of magnetic field can be shown in real-time and intuitively.

Based on a modified Maxwell-Wagner model, molecular dynamics is carried out to simulate the structural changes of ER (electrorheological) suspensions in a poiseuille flow field. The simulation results show that the flow assists in the collection of particles at the electrodes under a low pressure gradient, and the negative ER effect will show under a high pressure gradient. By analyzing the relationship curves of the shear stress and the pressure gradient in different relaxation time, it is found that for the same kind of ER suspensions materials, there is an optimal dielectric relaxation frequency.

A sandwich beam specimen was fabricated by treating with MR elastomers between two thin aluminum face-plates. Experiment was carried out to investigate the vibration responses of the sandwich beam with respect to the intensity of the magnetic field and excitation frequencies. The results show that the sandwich beams with MR elastomers cores have the capabilities of shifting natural frequencies and the vibration amplitudes decrease with the variation of the intensity of external magnetic field.

A further numerical study of the theory that the drag reduction in the turbulence is related to the viscosity profile growing linearly with the distance from the wall was performed. The constant viscosity in the Navier-Stokes equations was replaced using this viscosity model. Some drag reduction characteristics were shown comparing with Virk’s phenomenology. The mean velocity and Reynolds stress profiles are consistent with the experimental and direct numerical simulation results. A drag reduction level of 45% was obtained. It is reasonable for this linear viscosity model to explain the mechanism of turbulence drag reduction in some aspects.

A combined magnetorheological damper combined with rubber spring and magnetorheological damper is addressed. This type of damping device has inherited the merits of rubber spring and the magnetorheological damper. The test damping device is made up of combined magnetorheological damper, amplitude controller, signal collecting device, computer software for dynamic analysis, etc. When a zeromean and non-Gaussian white noise interfere with the device, a time series autoregressive(AR) model is conducted by using the sampled experimental data. Trispectrum and its slices analysis are emerging as a new powerful technique in signal processing, which is put forward for investigating the dynamic characteristics of the magnetorheological vibrant device. The present of trispectrum and its slices analysis change with the variation of controllable working magnetic field of the damper correspondingly. It is indicated that AR trispectrum and its slices analysis methods are feasible and effective for investigation of magnetorheological vibrant device.

In order to prepare special MRFs to satisfy the demands of tracked vehicle, two different carrier fluids were used to prepare MRFs. Preparation of MRF, which are based on carrier of special shock absorption fluid and 45# transformer oil, was finished. And characteristics of these samples were tested and analyzed. The results show that Tween-80 and Span-80 can improve the sedimentary stability, and the larger mass fraction can also increase the sedimentary stability. Using 45# transformer oil instead of special shock absorption fluid as a carrier of MRF, the shear yield stress remains nearly constant but the viscosity and the sedimentary stability are reduced. The MRF with diameter of 2.73 μm shows better sedimentary stability than that of the MRF with diameter of 2.30 μm, or 4.02 μm. Stearic acid obviously improves sedimentary stability and off-state viscosity, but has no function on the shear yield stress. In magnetic field of 237 kA/m, the shear yield stress of MRF based on special shock absorption fluid is 18.34 kPa and the shear yield stress of MRF based on 45# transformer oil is 14.26 kPa.

Higher order spectral analysis can be used to identify nonlinearities in the complex dynamical systems. This proposal shows that the contributions of the bispectrum, trispectrum, reconstructed bispectrum and reconstructed power spectrum in terms of the system frequency response function and elementary physical properties of the MR damping system. Subsequent estimates of the HOS based on the output stochastic oscillating signals appear distinct variation. An experimental platform for MR vibrating semi-active control is built, proper simplifications are presented, an AR(10) model is established with colored noises from the output signals. Comparison between power spectrum from second order moment function and bispectrum, trispectrum are taken. The later gives an indication of the correlation between the phases of different frequency components. Since time series model is a parametric model, the reconstructed bispectrum and power spectrum are smooth. It is demonstrated that the higher order spectra are effectively for recognition and description of nonlinear systems.

Magnetorheological elastomer (MRE) is a new kind of smart materials, its dynamic mechanic performances can be controlled by an applied magnetic field. MRE is usually used as a stiffness-changeable spring in the semi-active vibration absorber. In order to get perfect vibration control effect, low dynamic damping of MRE is need. But the dynamic damping of MRE was not studied deeply in the past. The dynamic damping of MRE was studied and analyzed. The influences of different test conditions including test strain amplitude, test frequency and test magnetic field were deeply studied. MRE sample and pure silicone rubber sample were prepared and tested under different conditions. The test results show that the main source of dynamic damping is the friction between iron particles and rubber matrix. And the friction is mainly influenced by the strain amplitude and test magnetic field.

The Rayleigh-Taylor(R-T) instability of ferrofluid has been the subject of recent research, because of its implications on the stability of stellar. By neglecting the viscosity and rotation of magnetic fluid, and assuming that the magnetic particles are irrotational and temperature insensitive, we obtain a simplified R-T instability model of magnetic fluid. For the interface tracing, we use five-order weighted essentially non-oscillatory(WENO) scheme to spatial direction and three-order TVD R-K method to time direction on the uniform mesh, respectively. If the direction of the external magnetic field is the same as that of gravity, the velocities of the interface will be increased. But if the direction of the external magnetic field is in opposition to the direction of gravity, the velocities of the interface will be decreased. When the direction of the external magnetic field is perpendicular to the direction of gravity, the symmetry of the interface will be destroyed. Because of the action which is produced by perpendicular external magnetic field, there are other bubbles at the boudaries which parallel the direction of gravity. When we increase the magnetic susceptibility of the magnetic fluids, the effects of external magnetic fields will be more distinct for the interface tracing.

The damping property of magnetorheological elastomers (MREs) is characterized by a modified dynamic mechanical-magnetic coupled analyzer. The influence of external magnetic flux density, damping of matrix, content of iron particles, dynamic strain and driving frequency on the MREs’ damping was investigated experimentally. The results indicate that the MREs’ damping property depends on the interfacial slip between the inner particles and the matrix. Different from the general composite materials, the interfacial slip in MRE is affected by the external applied magnetic field.

The influence of rheological parameters on vortex dynamics and the extent of drag reduction (DR) were deciphered via extensively analyzing the hi-fidelity direct numerical simulation results of the turbulent channel flow with polymer solutions. It has been observed that in all drag reduction regimes from the onset of DR to maximum drag reduction (MDR) limit, the Deborah number is defined as the product of an effective Weissenberg number, and the root mean square streamwise vorticity fluctuation remains O(1) in the near wall region. The ratio of the average lifetime of axial vortices to the vortex rotating duration decreases with increasing DR, and MDR is achieved when these time scales become nearly equal. Based on these observations a simple framework is proposed adequately to describe the influence of polymer additives on the extent of DR from onset to MDR as well as the universality of the MDR in flow systems with polymer additives.

The downward moving behavior of pellets in a 8 m² pellet shaft furnace with an internal vertical air channel and a drying bed was studied by means of a visualized model (1:15) and a top model (1:1). The visualized model experiment shows that the downward movement of pellets can be regarded as plug flow approximately inside the furnace except for the lower region of cooling zone due to the influence of the drained hopper. The top model experiment reveals that the pellet sizes increase along the moving direction because of the percolation phenomenon, which results in a decrease of the resistance coefficient and an increase of the gas flow rate from the furnace wall toward the furnace center.

The work principle of flat-plate structure under shearing mode is expounded based on a vertical type rheometer for MRF which combined data acquisition with treatment and result display. The formula to calculate shearing stress is deduced. Based on different recipe for MRF, experiments under different working gap length were done by altering the intensity of magnetic field. The rheological model for MRF was established and the relationships between shearing stress, viscosity and magnetic field intensity were deduced. Experiments indicate that MRF has the flowing characters: with an increase of the magnetic induction and the nominal shear rate, the shear stress of MRF increases. However, as the working gap decreases, the shear stress increases. MRF has shear thinning property under magnetic field.

Waxy crude oil exhibits complex shear-and-thermal-history-dependent non-Newtonian behaviors. In the past 10 years, driven by the petroleum industry, crude oil rheology has been an active field. Studies on crude oil rheology have been passing a way from simply relying on rheological measurements, through quantitative experimental simulation of shear and thermal history effects in pipelining, to recent development of correlation between flow properties and shear and thermal history. Currently, the study is toward quantitative inquiry of relations between the rheological behaviors and micro-structures of wax crystals as well as oil compositions. Advances achieved by the author’ team are summarized, including simulation of the thermal and shear history effects, correlations and computation of flow properties, fractal characterization of morphology and structure of wax crystals, relations of rheological behaviors to fractal dimension and oil compositions, and the most successful example of the application of rheology in crude oil pipelining. Future studies are prospected.

Different aging levels (RTFOT, PAV-10h, PAV-20h and PAV-30 h) of asphalt binders with various mass ratios of mineral powder to asphalt (0, 0.4, 0.8, 1.2, 1.6, 2.0) were used to investigate the rheological properties of aged asphalt binders with respect to their short and long terms aging characteristics. Viscosity test, dynamic shear test and creep test were conducted. The test results indicate that the viscosity of aged asphalt binder increases sharply with the extension of aging period. Complex shear modulus of aged asphalt increases, which indicates that the stiffness of asphalt binders can increase. The phase angle for aged asphalt binders reduces, which indicates that the elastic portion for viscoelastic property of asphalt binders increases. |G*|·sin δ increases after aging procedure which means that the fatigue resistance becomes poor. The creep test results show that creep strain curves varies remarkably for virgin and aged asphalt binders. The total strain during loading period and the permanent strain decreases significantly for aged asphalt binders, which implies that the elastic portion increases and the viscous portion decreases.

Equivalent Mohr-Coulomb yield criterion was established, and the relationship between different constitutive models was studied. The application of equivalent Mohr-Coulomb yield criterion in Ansys was achieved by means of transforming material parameters. The stability research aiming at the most common rock slope without conspicuous slide surface was accomplished, the methods of measurably assessing the stability of rock slope without conspicuous slide surface were explored, and the disadvantages of method of minimum slide-resisted reserve as dangerous slide path were pointed out. The results show that through the calculation and analysis of cases, the conception that measurable assessment of the stability of rock slope without conspicuous slide surface can be achieved under condition that equivalent Mohr-Coulomb yield criterion is validated. Its safety parameter formula is explicit in theory and credible in results. The results obtained are approximate to those obtained by using finite element intensity reducing method.

Long distance buried liquid-conveying pipeline is inevitable to cross faults and under earthquake action, it is necessary to calculate fluid-structure interaction(FSI) in finite element analysis under pipe-soil interaction. Under multi-action of site, fault movement and earthquake, finite element model of buried liquid-conveying pipeline for the calculation of fluid structure interaction was constructed through combinative application of ADINA-parasolid and ADINA-native modeling methods, and the direct computing method of two-way fluid-structure coupling was introduced. The methods of solid and fluid modeling were analyzed, pipe-soil friction was defined in solid model, and special flow assumption and fluid structure interface condition were defined in fluid model. Earthquake load, gravity and displacement of fault movement were applied, also model preferences. Finite element research on the damage of buried liquid-conveying pipeline was carried out through computing fluid-structure coupling. The influences of pipe-soil friction coefficient, fault-pipe angle, and liquid density on axial stress of pipeline were analyzed, and optimum parameters were proposed for the protection of buried liquid-conveying pipeline.

Based on the results of triaxial compressive creep tests for five kinds of rock under the different stress loading, unloading and cycle-loading-unloading conditions, the creep deformation is not only a function of stress and time, but also it has the corresponding relations to the triaxial stress-strain curves of rock. The deformation properties of soften-strain, harden-strain and ideal plasticity presented by conventional triaxial compressive test curves under the different stress states were utilized, and the creep characteristics, the creep starting stress and the different entire creep process curves of rock were studied systematically according to creep experiment results, and the relations of the triaxial stress-strain curves to the creeping starting stress, the terminating curve, the different creep processes, and the different creep fracture properties were established. The relations presented in this paper were verified partially by the creep experiment results of five types of rock.

In contrast to the traditional interpretation of shear bands in sand as a bifurcation problem in continuum mechanics, shear bands in sand are considered as high-strain phase (plastic phase) of sand and the materials outside the bands are still in low-strain phase (elastic phase), namely, the two phases of sand can coexist under certain condition. As a one-dimensional example, the results show that, for materials with strain-softening behavior, the two-phase solution is a stable branch of solutions, but the method to find two-phase solutions is very different from the one for bifurcation analysis. The theory of multi-phase equilibrium and the slow plastic flow model are applied to predict the formation and patterns of shear bands in sand specimens, discontinuity of deformation gradient and stress across interfaces between shear bands and other regions is considered, the continuity of displacements and traction across interfaces is imposed, and the Maxwell relation is satisfied. The governing equations are deduced. The critical stress for the formation of a shear band, both the stresses and strains inside the band and outside the band, and the inclination angle of the band can all be predicted. The predicted results are consistent with experimental measurements.

The yield stress of waxy crude oil is a fundamental parameter in the calculation of pipelining technique and analysis of flow safety for the heated oil transported through pipeline. Daqing crude oil was studied and the variation of yield stress with shear history was explored through simulation experiment of pipelining. It is found that the effect of throughput variation or shear rate on yield stress is not obvious. With the decrease of final dynamic cooling temperature, the yield stress of waxy crude oil decreases, but there exists a little increase at the beginning. The prediction model of yield stress for waxy crude oil under the condition of shutdown is developed and it can be used to predict the yield stress of Daqing crude oil at certain heating temperature, final dynamic cooling temperature and measurement temperature. For the 139 groups of yield stress data of Daqing crude oil from the simulation experiment of pipelining, the result of prediction with this model shows that the average relative deviation between the yield stress measured and predicted is 30.27%, and the coefficient of correlation is 0.962 3.

The experimental research on the non-Newtonian flow characteristic of a waxy crude oil was conducted through a rotational parallel-plates rheometer system. The test temperature is about 6.5 °C higher than its gel point. The shear stress and viscosity of the waxy crude oil show sophisticate non-Newtonian characteristics in the shear rate of 10⁻⁴–10² s⁻¹, in which the shear stress can be divided into three parts qualitatively, i.e. stress-up region, leveling-off region, and stress-up region. This indicates that there is a yielding process in shearing for the waxy crude oil at the experimental temperature, which is similar to the yield phenomenon in thixotropy-loop test discussed by CHANG and BOGER. Furthermore, the steady shear experiment after the pre-shear process shows that the stress leveling-off region at low shear rate disappears for the waxy crude oil and the stress curve becomes a monotonic climbing one, which demonstrates that the internal structure property presenting through yielding stress at low shear rate can be changed by shearing. The experimental results also show that the internal structure of waxy crude oil presenting at low shear rate has no influence on the shear viscosity obtained at the shear rate higher than 0.1 s⁻¹. The generalized Newtonian model is adopted to describe the shear-thinning viscosity property of the waxy crude oil at high shear rate.

The device that consists of tank and disk agitator for evaluation drag reduction agents (DRA) was established. The effect of DRA was defined by testing the changes of agitator torque that drives the disk rotation. The HG-DRA for oil pipeline from Linyi to Puyang was studied by agitator tank device. The relationships between the drag reduction rate and Reynolds number, concentration, balance time were studied. The best concentration and the highest Renords number for the best drag reduction rate were confirmed. The results show that the drag reduction rate tested in agitator tank is close to that in pipeline. The maximum error of drag reduction rate between pipeline and agitator tank is 18.3%, which indicates that the agitator tank device is available to evaluate the effect of DRA for pipeline and it also has the advantages of simple, easy to be operated and using small volume of oil. Those are very helpful for operaters to know the properties of DRA and operate pipeline well.

Rheological characteristics of fiber-modified asphalt mixture were investigated. Cellulous fiber, polyester fiber and mineral fiber were used as additives for asphalt mixture, and the dosages were 0.3%, 0.3%, 0.4%, respectively. Dynamic modulus test using superpave simple performance tester (SPT) was adopted to study the dynamic modulus and phase angle for the control mixture and fiber-modified ones at various temperatures and frequencies. Test results show that the rheological properties can be improved significantly by the addition of various fibers. The dynamic modulus increases with the increase of frequency, and the phase angle decreases with the increase of frequency. When various fibers are used, the dynamic modulus increases and phase angle decreases at each frequency. This indicates that the stiffness and the elastic portion of fiber-modified asphalt mixtures can be enhanced when various fibers are used, which results in the change of viscoelastic properties of mixtures. The creep test results show that the total strain and the permanent strain of asphalt mixtures during load-unload cycle can be significantly reduced, which results in the improvement of resistance to permanent deformation for asphalt mixtures containing various fiber additives. The Burgers model can be employed effectively to illustrate the rheological properties of fiber modified asphalt mixtures.

The effect of concrete creep on the pre-camber of a long-span pre-stressed concrete continuous rigid-frame bridge constructed by cantilever casting method was investigated. The difference of creep coefficients calculated with two Chinese codes was discussed. Based on the calculations, the pre-camber of a pre-stressed concrete continuous rigid-frame box bridge was computed for construction control purpose. The results show that the short-term creep coefficient and long-term creep coefficient calculated with the CC-1985 are larger than those calculated with the CC-2004, while the medium-term creep coefficient calculated with the CC-1985 is smaller than that calculated with the CC-2004. The difference of creep deformation calculated with these two codes is small, and the influences of concrete creep on the pre-camber for most of the segments are negligible. The deflections and stresses of the box girder measured during the construction stages agree very well with the predictions.

In the structural design of the high pier, in order to analyze the strength and structure stability, the pier was often considered a thin-walled structure. Elastoplastic incremental theory was used to establish the model of elastoplastic stability of high pier. By considering the combined action of pile, soil and pier together, the destabilization bearing capacity was calculated by using 3-D finite element method (3-D FEM) for piers with different pile and section height. Meanwhile, the equivalent stress in different sections of pier was computed and the processor of destabilization was discussed. When the pier is lower, the bearing capacity under mutual effect of pile, soil and pier is less than the situation when mutual effect is not considered; when the pier is higher, their differences are not conspicuous. Along with the increase of the cross-sectional height, the direction of destabilization bearing capacity is varied and the ultimate capacity is buildup. The results of a stability analysis example are almost identical with the practice.

Using resistivity as index and referring to the law about effect of slope to resistivity, the apparent resistivities of geophysical model concerned with unsteady rock type slope failure were calculated systematically by using the boundary integral equation method. After studying the feature of resistivity response of slope failure, the variety of resistivity during evolution of slope from steady to unsteady was found and the characteristics of resistivity response about slope failure was concluded. These make electrical exploring method for detecting the slip plane or structural plane of slope failure, evaluating the stability of the slope, and forecasting slope failure become true.

Considering the rheological properties of rock and soil body, and exploiting the merit of strength reduction technique, a theory of couple analysis is brought forward on the basis of strength reduction theory and rheological properties. Then, the concept and the calculation procedure of the safety factor are established at different time. Making use of finite element software ANSYS, the most dangerous sliding surface of the slope can be obtained through the strength reduction technique. According to the dynamic safety factor based on rheological mechanism, a good forecasting could be presented to prevent and cure the landslide. The result shows that the couple analysis reveals the process of the slope failure with the time and the important influence on the long-term stability due to the rheological parameters.

For most soft soil, the consolidation process and the creep process were coupled and the character of settlement time curve was obtained by the consolidation test at the same time. A simple and continuous function was presented to express the whole process of consolidation including immediate settlement stage, the primary consolidation stage and the secondary consolidation stage. And the features of the continuous function were analyzed. The results of the long-term (duration to 18 months) consolidation test on clays from the Chek Lap Kok formation proved the rightness of the method. In the end, the parameter meanings of the continuous function were discussed.

Petroleum and nature gas not only are important resources, but also are important strategic materials of our country. All methods the enhancing the producing degree of petroleum and natural gas reservoir, increasing single well production and extending the stimulation period of validity are important stratagem for petroleum and natural gas exploitation. Fracturing and acidizing are the main methods for stimulation as well as one of representative examples of rheology theory application in engineering. Based on analysis of low permeability reservoir characteristics, the fracturing and acidizing stimulation principles and main controlling factors were discussed. And the mechanical characteristics, chemical reaction and rheological behavior in the stimulation process were reviewed. Furthermore research trends afterwards including the material and fluid rheology in oil and natural gas production process, the deep rock fracture initiation and extension rheology, and the fracturing and acidizing application rheology were also proposed in this paper.

The influence of aging on the evolution of structural, morphological and rheological properties of neat asphalt was investigated by Fourier transform infrared (FTIR), atomic force microscopy (AFM) and dynamic shear rheometer (DSR), respectively. Asphalt was suffered under 20 W/m² of UV radiant intensity and under the condition of aging time (0, 48, 96 and 144 h) with film thickness of 100 μm and film thickness of 50, 100, 200 and 500 μm after aging for 120 h, respectively, at certain UV radiant intensity 20 W/m². Rheological results tested by DSR exhibit higher the complex shear (stiffness) modulus (G*) and lower phase angle (δ), compared to the virgin at the same test condition. The compositions analysis of asphalt before and after aging show an increase of carbonyl and sulfoxides, while a decrease of aromatic functional groups. With the increase of the component of asphaltene, obvious agglomerates of asphalten appear in neat asphalt surfaces after aging.

There are two mechanisms of the coarse surface asperity resistance effect and rubbing resistance effect in the course of the soft rock structural surface creep, of which the former plays a dominant role in hindering the deformation in the starting creep phase, so that the structural surface creep usually displays the strong surface roughness effect, and so does the latter when the asperities in the coarse surface were fractured by shearing. Under the low stress condition, there are only two phases of the decelerating creep and the constant creep for the soft rock structural surface, and as the stress increases and overcomes the rubbing resistance, the accelerating creep failure of the structural surface will happen suddenly. Therefore, a multiple rheological model, which combines the nonlinear NEWTON body (NN) of a certain mass and the empirical plastic body (EM) with the classical SAINT VENANT body, NEWTON body, KELVIN body and HOOKE body, could be used to comprehensively describe the creep characteristics of the soft rock structural surface. Its mechanical parameter values will vary owing to the different surface roughness of the structural surface. The parameters of G_H, G_K and η_L are positively linearly correlative to the surface roughness. The surface roughness and m are negative exponential function correlation. The long-term strength τ_S is positively correlative to the surface roughness.

The characteristics of high-filled embankment rheological settlement were analyzed; mechanical calculation model of high-filled embankment rheological settlement during constructing and running period was also put forward. Combining the macroscopic and microscopic deformation properties of the engineering soil grain, its constitutive model was set up and its characters were fully revealed, at the same time, its practical calculation formula under the action of dead-weight load was derived, which is feasible by analysis and comparison.

Through unconfined compressive strength test, influencing factors on compressive strength of solidified inshore saline soil with SH lime-ash, ratio of lime-ash(1:K), quantity of lime-ash, age, degree of compression and salt content were studied. The results show that because inshore saline soil has special engineering characteristic, more influencing factors must be considered compared with ordinary soil for the perfect effect of solidifying.

Based on the engineering background of a soft rock roadway in Qinan Coal Mine 82 Area, Huaibei Mining Group, three creep models with different support patterns in soft rock roadway were established by using geotechnical software of FLAC^2D. According to the calculation results of different models, the change law of mechanical properties with the time of bolt-grouting support structure was obtained. Furthermore, for the test bolt-grouting support roadway, the deformation law of surrounding rock got by underground industrial experiment and field observation accords with the creep law got by numerical calculation. The results of numerical calculation and field observation show that, compared with other supports, the creep of bolt-grouting support roadway enters the steady-state creep stage from tertiary creep stage ahead, the deformations of roof, floor and two sides are decreased greatly, the plastically deforming area in surrounding rock is reduced obviously, and the distribution ranges of maximum and minimum principal stress are shrank obviously. All those fully show that the bolt-grouting support has its remarkable advantages in controlling surrounding rock creep and improving the whole strength of surrounding rock and self-bearing capacity.

In order to study the rheological properties of red stone granular soil, a series of rheological experiments were executed on large tri-axial rheological apparatus. Under 100, 200 and 300 kPa confining stress conditions, the rheological tests were carried out. These experiment results showed that the stress conditions, especially the stress level were the critical influencing factors of the rheological deformation properties. Under the low stress level (S=0.1), the granular soil showed the elastic properties, and there was no obvious rheological deformation. Under the middle stress level (0.2<S⩽0.6), creep curves showed the linear viscoelastic rheological properties. However, under the high stress level (S>0.8) creep curves showed the non-linear viscous plastic rheological properties. Especially, under the stress level of S=1.0, the accelerated rheological phase of creep curves occurred at early time with a trend of failure. The stress level had obvious effects on the final rheological deformation of the soil sample, and the final rheological deformation increments nonlinearly increased with stress level. The final rheological deformation increment and step was little under low stress level, while it became large under high stress level, which showed the nonlinearly rheological properties of the granular soil. The confining pressure also had direct effects on final rheological deformation, and the final rheological deformation linearly increased with confining pressure increments.

In-plane shear crack sub-critical propagation of rock at high temperature was studied by finite element method and shear-box (i.e. compression-shear) test with newly designed electrically conductive adhesive method. Numerical and experimental results show that the normalized shear (Mode II) stress intensity factors, K_II^T/K_II0 is decreased as the temperature increases because high temperature can improve stress distribution at crack tip and reduce the Mode II stress intensity factor. Microscopic features of fractured surface are of little pits and secondary micro-cracks in the vicinity (1.5–4.0 mm) of the crack tip. The chevron-shape secondary cracks gradually merge in the length of about 4–5 mm and disappear along the direction of crack propagation. Stable shear crack propagation time is increased with the increasing temperature while the stable shear crack propagation rate is decreased with the increasing temperature, since high temperature can increase the shear (Mode II) fracture toughness and prevent the crack growth. It is necessary to ensure the ligament of specimen long enough to measure the maximum unstable crack propagation rate of rock.

It is important and profound to quantitatively study the relation between rheology and microstructure for development of the microstructural mechanism of crude oil rheology and even for the waxy crude oil pipelining. However, due to the high complexity and irregularity of wax crystal morphology, quantitative characterization is hard to achieve. This has hampered further study on the rheology—microstructure relationship. A new approach combined the fractal geometry and the stereology theory is presented for quantifying the intricate wax crystal morphology and structure. Based on the characterization, the effects of microstructures and oil composition on the waxy crude viscosities are analyzed quantitatively. It further validates the previous qualitative research and enriches understanding into the microstructural mechanism of waxy crude oil rheology.

Based on constitutive theory of viscoelasticity, the viscoelastic behaviour of concrete pile was investigated. The influence of viscosity coefficient on the stress, displacement and velocity response was discussed. With the increase of viscosity coefficient, the amplitude of stress wave decreases, and the maximum value of the stress wave shifts to deeper position of the pile. In other words, the viscosity coefficient behaves as lag effect to stress wave.

In order to study the interaction between transverse isotropy rock mass and supporting structure, the laboratory tests for rock sampled from the slope at expressway project were carried out, and the parameters of elasticity for transverse isotropic rock were determined by the uniaxial compression tests for rock sample with different strike of stratification plane. Then, based on the relationship of stress—stain for transverse isotropic rock mass, the analytical model was established for the interaction between transverse isotropic rock mass and frame beam with pre-stressed anchor cable. Furthermore, the conception of the best anchorage-angle in pre-stressed anchor cable was proposed. At last, the parameters of the interaction between transverse isotropy rock mass and frame beam with pre-stressed anchor cable were investigated by finite element method, and the best anchorage-angle in pre-stressed anchor cable was obtained. The rules of the influence of the directivity of stratification plane on supporting structure were determined. The results show that the analytical model and numerical method on the design of pre-stressed anchor cable with frame beam supporting for transverse isotropy rock slope are reasonable and reliable in practical engineering design.

In order to optimize plastic viscosity of 18 mPa·s circulating micro-bubble drilling fluid formula, orthogonal and uniform experimental design methods were applied, and the plastic viscosities of 36 and 24 groups of agent were tested, respectively. It is found that these two experimental design methods show drawbacks, that is, the amount of agent is difficult to determine, and the results are not fully optimized. Therefore, multiple regression experimental method was used to design experimental formula. By randomly selecting arbitrary agent with the amount within the recommended range, 17 groups of drilling fluid formula were designed, and the plastic viscosity of each experiment formula was measured. Set plastic viscosity as the objective function, through multiple regressions, then quadratic regression model is obtained, whose correlation coefficient meets the requirement. Set target values of plastic viscosity to be 18, 20 and 22 mPa·s, respectively, with the trial method, 5 drilling fluid formulas are obtained with accuracy of 0.000 3, 0.000 1 and 0.000 3. Arbitrarily select target value of each of the two groups under the formula for experimental verification of drilling fluid, then the measurement errors between theoretical and tested plastic viscosity are less than 5%, confirming that regression model can be applied to optimizing the circulating of plastic-foam drilling fluid viscosity. In accordance with the precision of different formulations of drilling fluid for other constraints, the methods result in the optimization of the circulating micro-bubble drilling fluid parameters.

Low-permeability dense reservoirs, including micro-fractured reservoirs, are commonly characterized by high content of clay substances, high original water saturation, high sensitivity to invasive fluids, high capillary pressure, complicated structure and anisotropic, high flow-resistance and micro pore throats etc,. Generally they also have lots of natural micro fractures, probably leading to stress sensibility. Main damaging factors in such reservoirs are water-sensibility and water-blocking caused by invasive fluids during drilling and production operations. Once damaged, formation permeability can rarely recovered. Numerous studies have shown that damaging extent of water-blocking ranges from 70% to 90%. Main damaging mechanisms and influencing factors of water-blocking were systematically analyzed. Also some feasible precaution or treating approaches of water-blocking were put forward. In a laboratory setting, a new multi-functional drilling fluid composed mainly of amphion polymer, sulfonation polymer, high effectively preventive water-blocking surfactants, ideal packing temporary bridging agents (TBA) and film-forming agents, etc., were developed. New low-damage drilling fluids has many advantages, such as good rheological properties, excellent effectiveness of water-blocking prevention, good temporary plugging effect, low filtration and ultra-low permeability (API filtration⩽5 mL, HTHP filtration⩽10 mL, mud cake frictional coefficient⩽0.14, permeability recovery>81%), can efficiently prevent or minimize damage, preserve natural formation and enhance comprehensive development-investment effect in TUHA Jurassic dense sandstone reservoir formation with low-permeability, the only one developing integrated condense gas field. Some references can be provided to similar reservoir formations.

Shear resistance properties of the virgin bitumen and modified bitumen binders with Tafpack Super (TPS) modifier and SBS modified bitumen were discussed. Dynamic shear rheometer (DSR) was used to measure the laboratory creep data for these binders over a wide range of constant shear stresses at 20 °C to characterize the shear creep behaviors of all kinds of asphalt binders, and the rutting test system was used to investigate the permanent deformation of porous asphalt mixtures using the above bitumen binders for a fixed compressive stress. The shear strain rate and shear creep modulus were used to characterize the shear creep behavior of the TPS modified bitumen, and the rutting test results were used to show the consistency of porous asphalt mixtures with the bitumen binders. Results indicate that a distinction of shear creep strain can be made among different contents of TPS modified bitumen at the same stress level, where the shear creep strain-time response curve of the SBS modified bitumen binder is between the curves of the 8% TPS and 12% TPS modified bitumen binders. The shear strain rate and the shear creep modulus of the TPS modified bitumen binders are obtained to compare with those of the SBS modified bitumen binder which results in the same trend as the shear creep strain-time response curve. Permanent deformation results of all the porous asphalt mixtures from the rutting test show reasonable agreement with the findings of the shear strain rates and shear creep modulus over the range of shear stress levels.

The bending creep and its disturbance effects of red sandstone rock beam and oil shale rock beam were studied by adopting the self-developed gravitation level style rock creep test machine and bending creep test system, and the constitutive equations were established. It is found that fracture morphology of rock beams under no disturbance load is regular, cracking position of fractures is on part of loading concentration, the crack starts from a neutral plane. However, fracture morphology of rock beams under disturbance load is irregular, cracking position of fractures deviates from a neutral plane. Delayed instability of rock beam occurs for some time under constant disturbance load. When disturbance load is beyond a certain range, suddenly instability of occurs rock beam in a certain time. The results show that there is a guiding significance for creep stability in the geotechnical engineering fields.

The viscoelastic behavior of polyacrylamide solution is crucial for its application in various industries. The mixed polyacrylamide solution was prepared by mixing polyacrylamide with different relative molecular masses according to the defined mass fraction. The viscosity and elasticity of mixed polyacrylamide solution were separately tested with RS150 rheometer and capillary breakup extensional rheometer and compared with those of the single polyacrylamide solution which is directly provided by manufacturer without any mixing. The results indicate that the mixed and single polyacrylamide solutions have the same shear viscosity and intrinsic viscosity. However, some mixed polyacrylamide solutions have higher elasticity than single polyacrylamide solution. The flow resistance of mixed polyacrylamide with higher elasticity is also greater than that of single polyacrylamide solution in porous medium. This paper presents an effective method of mixing polyacrylamides with different relative molecular masses, which can enhance the elasticity of polyacrylamide solution and flowing resistance through porous medium.

To understand the high strain rate deformation mechanism and determine the grain size, strain rate and porosity dependent yield strength of nanocrystalline materials, a new mechanical model based on the deformation mechanism of nanocrystalline materials under high strain rate loading was developed. As a first step of the research, the yield behavior of the nanocrystalline materials under high strain rate loading was mainly concerned in the model and uniform deformation was assumed for simplification. Nanocrystalline materials were treated as composites consisting of grain interior phase and grain boundary phase, and grain interior and grain boundary deformation mechanisms under high strain rate loading were analyzed, then Voigt model was applied to coupling grain boundary constitutive relation with mechanical model for grain interior phase to describe the overall yield mechanical behavior of nanocrystalline materials. The predictions by the developed model on the yield strength of nanocrysatlline materials at high strain rates show good agreements with various experimental data. Further discussion was presented for calculation results and relative experimental observations.

Shear-box (i.e. compression-shear) test and newly designed electrically conductive adhesive method were used to measure shear crack sub-critical propagation time and rate of sandstone specimen. Different cubic specimens with and without holes were tested to study the effect of holes on the shear crack sub-critical propagation. Numerical and experimental results show that three independent variables of hole, the interval distance S, the distance between the center of hole and the crack tip L, and hole radius R, have different contribution to the ratio of stress intensity factor of the specimen with holes to that of the specimen without hole, K_II/K_II0. Increasing S and decreasing L and R will result in the decrease of K_II/K_II0 and help crack arrest. The weight relation of the independent variables for K_II/K_II0 is S>L>R. The specimen DH3 with the largest value of S and the smallest values of L and R has the longest sub-critical crack propagation time and the smallest sub-critical crack propagation rate. Adding two suitable holes symmetrically to the original crack plane in rock specimen is considered to be a potential method for crack arrest of rock.

The rheological properties of two kinds of oil-based drilling fluids with typically composition were studied at pressures up to 138 MPa and temperatures up to 204 °C using the RheoChan 7400 Rheometer. The experimental results show that the apparent viscosity, plastic viscosity and yield point decrease with the increase of temperature, and increase with the increase of pressure. The effect of pressure on the apparent viscosity, plastic viscosity and yield point is considerable at ambient temperature. However, this effect gradually reduces with the increase of temperature. The major factor influencing the rheological properties of oil-based drilling fluids is temperature instead of pressure in the deep sections of oil wells. On the basis of numerous experiments, the model for predict the apparent viscosity, plastic viscosity and yield point of oil-based drilling fluids at high temperature and pressure was established using the method of regressive analysis. It is confirmed that the calculated data are in good agreement with the measured data, and the correlation coefficients are more than 0.98. The model is convenient for use and suitable for the application in drilling operations.

Based on deep analysis of ASP/oil emulsions flow behavior characteristic, a mathematical description of non-Newtonian emulsion was developed, and variation of rheological behaviors along the percolation flow direction was given. The effects of emulsions rheological behavior on oil recovery were quantity researched by a 2-D positive rhythm profile geological model. The result shows that the high viscosity and reduction of water phase permeability by emulsification can improve low-middle layer flow rate and enhance sweep efficiency, and the enhancement degree is related with emulsification degree. The study result can be used as reference for scheme design and production performance forecast during ASP flooding.

In order to research start-up pressure wave propagation mechanism and determine pressure wave speed in gelled crude oil pipelines accurately, experiment of Large-scale flow loop was carried out. In the experiment, start-up pressure wave speeds under various operation conditions were measured, and effects of correlative factors on pressure wave were analyzed. The experimental and theoretical analysis shows that thermal shrinkage and structural properties of gelled crude oils are key factors influencing on start-up pressure wave propagation. The quantitative analysis for these effects can be done by using volume expansion coefficient and structural property parameter of gelled crude oil. A new calculation model of pressure wave speed was developed on the basis of Large-scale flow loop experiment and theoretical analysis.

In order to analyze mechanism of casing damage, the uniaxial compression experiment and creep experiment of interbedded mudstone samples from Sanan development area of Daqing Oilfield under different water contents were carried out. The changes of the mudstone’s mechanical parameters and creep characteristics with the increment of water saturation were studied. The results indicate that the rock strength and elastic modulus decrease rapidly with the increment of water content, at the same time, the creep strain and creep strain rate of steady state increase with the increment of water content, and also the steady state creep strain rate is enhanced with the increment of deviatoric stress. Through the creep characteristic curves, a non-linear creep constitutive equation of mudstone considering the change of water contents is established, which will be used in future numerical analysis.