The design of a segmented-rod projectile is often simplified into an ideal one in theoretical analysis for the convenience of modeling of its performance. But the actual performance of non-ideal segmented-rod projectiles over the impact velocity range in practical applications was rarely explored. AUTODYN numerical code is used to investigate the influence of the component design upon the penetration performance of non-ideal segmented-rod projectiles over a wide range of impact velocities, which can be used to guide the optimal design of weaponry segmented-rod projectiles.

Numerical method is popular in analysing the blast wave propagation and interaction with structures. However, because of the extremely short duration of blast wave and energy transmission between different grids, the numerical results are sensitive to the finite element mesh size. Previous numerical simulations show that a mesh size acceptable to one blast scenario might not be proper for another case, even though the difference between the two scenarios is very small, indicating a simple numerical mesh size convergence test might not be enough to guarantee accurate numerical results. Therefore, both coarse mesh and fine mesh were used in different blast scenarios to investigate the mesh size effect on numerical results of blast wave propagation and interaction with structures. Based on the numerical results and their comparison with field test results and the design charts in TM5-1300, a numerical modification method was proposed to correct the influence of the mesh size on the simulated results. It can be easily used to improve the accuracy of the numerical results of blast wave propagation and blast loads on structures.

Inert metal explosive, a new kind of explosive, is a mixture of high explosive and inert metal particle. When this kind of explosive is detonated, an inert metal particle flow will be formed by the explosive product driving. To determine the characteristics of the movement of the metal particle flow, a series of aluminium plates were designed to be the targets on which the metal particle flow impacted. The test result was presented and a numerical model was set up to analyze the impact of the high speed inert metal particles on aluminium plate. Based on the numerical analysis, the relationship between the characteristic of the mark on the target plate and the initial condition of the inert metal particles was proposed. From the analysis of the impact on target plates, more information about the movement of the metal particles could be reconstructed.

The hazard caused by the fragments of damaged structures is usually significant in accidental explosions or hostile blast events. A reliable and efficient method to estimate probable fragment size, velocity and launch distance will be useful to assess and design countermeasures to mitigate the possible fragment hazards. This paper presents a numerical method for predicting the size and launch distance of the fragments caused by explosive damage of masonry wall. Numerical simulations with different scaled distances are carried out, and the statistical distribution functions of the fragment size and launch distance in terms of the scaled distance are derived.

In order to evaluate the capacity of reinforced concrete (RC) structures subjected to blast loadings, the damaged plasticity model for concrete was used in the analysis of the dynamic responses of blast-loaded RC structures, and all three failure modes were numerically simulated by the finite element software ABAQUS. Simulation results agree with the experimental observations. It is demonstrated that the damaged plasticity model for concrete in the finite element software ABAQUS can predict dynamic responses and typical flexure, flexure-shear and direct shear failure modes of the blast-loaded RC structures.

The ratios of depth of penetration (DOP) of different targets under the same penetration condition was investigated according to the dimensionless formula of DOP of different targets penetrated by a non-deformable projectile. Results show that various targets may be equivalent to each other. The applicable range of the equivalence and the feasibility of targets substitution were discussed by integrating the available test data.

Under extreme loading condition, a shelter will provide a safe place to protect people from injury caused by blast wave and fragments. In order to save resource and reuse waste materials, a new design concept for blast protection shelter was explored. The new construction was composed of I-section steel panel or C-channel steel panel filled with recycled concrete aggregate. The compaction process of the recycled concrete aggregate filled in the steel construction was experimentally investigated. A single storey shelter based on the proposed design concept was numerically simulated by using LS-DYNA software. In the 3D numerical model, three walls were designed using I-section steel and one wall using C-channel steel, and all of the four walls were filled with recycled concrete aggregate. The penetration analysis was done by using ConWep. Some penetration tests were also carried out by using a gas gun. It is found that the proposed shelter based on the design concept is effective for blast protection.

Projectile made of carbon fiber composite material shell and metal warhead penetrates concrete target at speeds of 336 m/s, 447 m/s and 517 m/s. The angles between the perpendicular of target surface and projectile axis are 0° and 30°. The thickness of concrete target is 200 mm and the compression strength is 30 MPa. The experimental results indicate that the strength of composite material structure is high. Composite projectile can go through concrete target without fiber segregation and breakage. The percent fill is 18.5% in the composite material projectile. It is about twice as that of metal projectile, if the density of metal is taken as 7.8 g/cm³. Comparing with metal projectile, low-density, high-strength composite material can lessen projectile weight, improve charge-weight ratio of detonator and enhance destructive powder.

With the increase of domestic gas consumption in cities and towns in China, gas explosion accidents happened rather frequently, and many structures were damaged greatly. Rational physical design could protect structures from being destroyed, but the character of explosion load must be learned firstly by establishing a correct mechanical model to simulate vented gas explosions. The explosion process has been studied for many years towards the safety of chemical industry equipments. The key problem of these studies was the equations usually involved some adjustable parameters that must be evaluated by experimental data, and the procedure of calculation was extremely complicated, so the reliability of these studies was seriously limited. Based on these studies, a simple mathematical model was established in this paper by using energy conservation, mass conservation, gas state equation, adiabatic compression equation and gas venting equation. Explosion load must be estimated by considering the room layout; the rate of pressure rise was then corrected by using a turbulence factor, so the pressure-time curve could be obtained. By using this method, complicated calculation was avoided, while experimental and calculated results fitted fairly well. Some pressure-time curves in a typical rectangular room were calculated to investigate the influences of different ignition locations, gas thickness, concentration, room size and venting area on the explosion pressure. The results indicated that: it was the most dangerous condition when being ignited in the geometry centre of the room; the greater the burning velocity, the worse the venting effect; the larger the venting pressure, the higher the peak pressure; the larger the venting area, the lower the peak pressure.

Experimental investigation into impact-resistant behavior of reactive powder concrete (RPC)-filled steel tubular columns was conducted, and dynamic response of the columns under axial impact loading was studied by means of numerical simulation method. Increase coefficient of load carrying capacity and ratio of load carrying capacity between steel tube and RPC core of columns were obtained.

Based on the characteristics of 1D waves, the stress uniformity process in specimens under different loading conditions of rectangular and half-sine input waves was analyzed in split Hopkinson pressure bar (SHPB) test. The results show that the times of an elastic wave propagating from one end to the other in a specimen to attain stress equilibrium, is related to input waveforms and relative mechanical impedance between the specimen and the input/output bars. Hereinto, with the increae of the relative impedance, the times decreases under rectangular input waves loading, while it increases under half-sine input wave loading. The dimensionless stress value of specimen corresponding to the status of stress equilibrium increases with the increase of the relative mechanical impedance. However, the dimensionless stress value under half-sine input wave loading is significantly lower than the value under rectangular input wave loading for specimen with low mechanical impedance, and the relative differentia of the dimensionless stress values under two loading conditions decreases with the increase of the relative mechanical impedance. In general, the forced state of specimen with relatively low mechanical impedance under half-sine input wave loading is evidently superior to the state under rectangular input wave loading in SHPB test, and the advantages of forced state under half-sine input wave loading turns weak with the increase of the relative mechanical impedance.

The displacements and geometry of the rock blocks and the properties of the rock structure play an important role in the stability of tunnels. Based on the key block model, the dynamic instability analysis of underground tunnel subjected to intensive short-time compressional wave was conducted. The instability of the tunnel caused by the spallation and the inertial effect was distinguished. And the influence of the roof contour curvature of tunnel was also determined.

The spallation of the concrete slabs or walls resulting from contact detonation constitutes risk to the personnel and equipment inside the structures because of the high speed concrete fragments even though the overall structures or structural members are not destroyed completely. Correctly predicting the damage caused by any potential contact detonation can lead to better fortification design to withstand the blast loadings. It is therefore of great significance to study the mechanism involved in the spallation of concrete slabs and walls. Existing studies on this topic often employ simplified material models and 1D wave analysis, which cannot reproduce the realistic response in the spallation process. Numerical simulations are therefore carried out under different contact blast loadings in the free air using LS-DYNA. Sophisticated concrete and reinforcing bar material models are adopted, taking into account the strain rate effect on both tension and compression. The erosion technique is used to model the fracture and failure of materials under tensile stress. Full processes of the deformation and dynamic damage of reinforced concrete (RC) slabs and plain concrete slabs are thus observed realistically. It is noted that with the increase of quantity of explosive, the dimensions of damage crater increase and the slabs experience four different damage patterns, namely explosive crater, spalling, perforation, and punching. Comparison between the simulation results of plain concrete slabs and those of RC slabs show that reinforcing bars can enhance the integrity and shearing resistance of the slabs to a certain extent, and meanwhile attenuate the ejection velocity and decrease the size of the concrete fragments. Therefore, optimizing reinforcement arrangement can improve the anti-spallation capability of the slabs and walls to a certain extent.