VAlN coating is of particular interest for dry cutting applications owing to its low-friction and excellent abrasiveness. Nano-multilayer structure is designed to tailor the properties of VAlN coating. In this work, a series of VAlN/Si3N4 nano-multilayer coatings with varied Si3N4 layer thicknesses were prepared by reactive sputtering method. The microstructure and mechanical properties of the coatings were both investigated. It is revealed that Si3N4 with a shallow thickness (∼0.4 nm) was crystallized and grown coherently with VAlN, showing a remarkable increase in hardness compared to VAlN monolayer coating. The hardness of coherently VAlN/Si3N4 nano-multilayer coatings reached to 48.7 GPa. With further increase of Si3N4 layer thickness, the coherent growth of nano-multilayers was terminated, showing amorphous structure formed in nano-multilayers and the hardness was declined. On the other hand, when Si3N4 layer thickness was 0.4 nm, the friction coefficient of VAlN/Si3N4 nano-multilayer coating was almost equal to that of VAlN monolayer coating, which was attributed to the crystallization of Si3N4 and the produced coherent interfaces between VAlN and Si3N4 for the hardening effect of nano-multilayer coatings. Upon further increase of Si3N4 layer thickness, pronounced improvement of friction coefficient in VAlN/Si3N4 nano-multilayer coating was observed.
In order to further improve the driving performance of ionic polymer metal composites (IPMCs), Nafion/graphene quantum dots (GQDs) hybrid membranes incorporating GQDs with various contents of 0, 0.1 wt.%, 0.5 wt.%, 1.0 wt.%, 2.0 wt.% and 4.0 wt.% were fabricated by solution casting, and then IPMCs were manufactured by electroless plating. The water contents and elastic moduli of the hybrid membranes were tested. The morphology characteristics of the hybrid membranes and the IPMCs were observed, and the current, AC impedance, blocking force and displacement of the IPMCs were measured. The results show that the elastic modulus of the hybrid membranes decreases, the water content increases, and the actuation performance of the IPMCs improves significantly after the addition of GQDs. IPMC with 1.0 wt.% GQDs exhibits the best driving property. Compared with the IPMC without GQDs, the working current, ion conductivity, blocking force, and tip displacement increase by 94.67%, 311.11%, 53.66%, and 66.07%, respectively. These results lay a solid foundation for the preparation of IPMCs with high performance, and further broaden their applications in biomedical devices and bionic robots.
In order to improve the low ductility of the Mo-Ni alloy, Fe is added and the effects of Ni/Fe mass ratio on the densification behavior, microstructure evolution and mechanical properties of alloy were investigated. The experimental results show that when iron is added to 95Mo-5Ni alloy, the formation of brittle intermetallic phase δ-MoNi at the grain boundary is avoided. Meanwhile, the grain growth of Mo is also effectively inhibited in the sintering process. However, the addition of iron reduces the degree of densification of alloy since the activation effect of Ni is superior to that of Fe. From the experimental results, it could be concluded that the maximum hardness and bending strength are achieved by 95Mo-1.5Ni-3.5Fe alloy, which are HV 614 and 741 MPa, respectively. Combined with the analyses of bending fracture mechanism, the improvement relative to Mo-Ni alloy is likely attributed to the inhibition of the brittle phase.
A series of glass are synthesized via a melt quenching technique based on the Li2O-NiO-P2O5 system. The concentration of nickel oxide varies from 5% to 15% in molar fraction. XRD pattern verifies the amorphous nature of prepared glass samples with 5%, and 10% nickel oxide in molar fraction. While Li3P and Ni2P4O12 phases are precipitated with a high nickel content up to 15% in molar fraction. As nickel is substituted for lithium, a systematic increase in glass transition temperature (Tg) and glass softening temperatures (Ts) is observed. This is greatly related to the increased structure, coherence in the glass network. Structural investigation showed that Ni2+ spectra are present in both octahedral and tetrahedral sites. Physical properties such as glass density ((2.38±0.1)−(2.46±0.1) g/cm3), and molar volume ((42.28±0.1)−(39.15±0.1) cm3/mol) are examined. The NiO/Li2O replacements led to a decrease in the dissolution rate of the resultant amorphous materials from 1.53×10−5 to 3.20×10−6 g/(cm2·min). Thermal expansion coefficients CTE of the glasses are diverse from 157×10−7to 96×10−7 °C−1 over the temperature range of 25 −250 °C. The prepared glasses are expected to be useful as a low-temperature sealing material.
A series of InxSb2−xS3 nanosheets modified g-C3N4 (InxSb2−xS3-TCN) heterojunctions with different g-C3N4 contents were fabricated by an in situ deposition method. All the InxSb2−xS3-TCN composites were applied as photocatalysts in Cr(VI) polluted water treatment and the results displayed that InxSb2−xS3-TCN could effectively remove Cr(VI) under visible light through synergistic effects of adsorption and photocatalytic reduction. Especially, InxSb2−xS3-TCN-70 (70 mg g-C3N4) exhibited the most excellent adsorption and photocatalytic reduction performance among all composites, which possessed a high equilibrium adsorption capacity of 12.45 mg/g in a 30.0 mg/L Cr(VI) aqueous solution, and reduced Cr(VI) to Cr(III) within 10 min under visible light irradiation. DRS and PL results indicated that the interfacial coupling effect between g-C3N4 and InxSb2−xS3 enhanced the utilization efficiency of visible light and suppressed photoinduced carrier recombination, which improved the photocatalytic activity of composites. Moreover, the photocatalyst exhibited satisfactory reduction activity and good stability after 5 cycles of Cr(VI) adsorption-photoreduction.
Lithium (Li)-rich manganese (Mn)-based cathode Li1.2Ni0.13Co0.13Mn0.54O2 (LRNCM) has attracted considerable attention owing to its high specific discharge capacity and low cost. However, unsatisfactory cycle performance and poor rate property hinder its large-scale application. The fast ionic conductor has been widely used as the cathode coating material because of its superior stability and excellent lithium-ion conductivity rate. In this study, Li1.2Ni0.13Co0.13Mn0.54O2 is modified by using Li1.4Al0.4Ti1.6(PO4)3 (LATP) ionic conductor The electrochemical test results show that the discharge capacity of the resulting LRNCM@LATP1 sample is 198 mA·h/g after 100 cycles at 0.2C, with a capacity retention of 81%. Compared with the uncoated pristine LRNCM (188.4 mA·h/g and 76%), LRNCM after the LATP modification shows superior cycle performance. Moreover, the lithium-ion diffusion coefficient DLi+ is a crucial factor affecting the rate performance, and the DLi+ of the LRNCM material is improved from 4.94×10−13 to 5.68×10−12 cm2/s after modification. The specific capacity of LRNCM@LATP1 reaches 102.5 mA·h/g at 5C, with an improved rate performance. Thus, the modification layer can considerably enhance the electrochemical performance of LRNCM.
The relationship between viscosity/yield stress and flotation rate in different chalcopyrite and lizardite concentrations was investigated by zeta potential measurements, rheological tests, flotation experiments, and Derjguin-Landau-Verwey-Overbeek theoretical calculation. Results indicated that the concentration of minerals would affect the viscosity and yield stress of the slurry. That is, the viscosity/yield stress in the slurry rises accordingly when the concentration of minerals increases. The increase in viscosity/yield stress in slurry is also unfavorable to the enrichment of chalcopyrite but is conducive to the entrainment of lizardite in either single or binary system. Specifically, the flotation rate of chalcopyrite decreases while that of lizardite increases with the rise in viscosity/yield stress.
The response surface methodology (RSM) was used to optimize the operating parameters during the bioleaching of Jinchuan high-magnesium nickel sulfide ore. The particle size, acid addition, pulp density and inoculation amount were chosen as the investigated parameters. To maximize the leaching efficiency of nickel, copper, cobalt and minimize the dissolution of magnesium and iron ions, the model suggested a combination of optimal parameters of particles less than 0.074 mm being 72.11%, sulfuric acid addition being 300 kg/t, pulp density being 5% and inoculation amount being 12.88%. Under the conditions, the average results of three parallel experiments were 89.43% of nickel leaching efficiency, 36.78% of copper leaching efficiency, 84.07% of cobalt leaching efficiency, 49.19% of magnesium leaching efficiency and 0.20 g/L of iron concentration. The model indicated that the most significant factor in response of the leaching efficiency of valuable metal is the particle size, and the most significant factor in response to the leaching efficiency of harmful ions (Mg2+) is the amount of sulfuric acid addition. And according to the suggested models, no significance of the interaction effect between particle size and acid addition was shown. Under the optimized parameters suggested by models, the valuable metals could be separated from harmful ions during the bioleaching process.
Without considering the influence of heat, existing fractal contact models are not applicable to analyze the contacts when the temperature changes. For this problem, the normal load model and the normal stiffness model of thermal elasto-plastic contact of rough surfaces are developed respectively in this paper. The proposed model is based on the normal contact mechanics model of fractal theory of anisotropic and thermal elasto-plastic contact theory which can be used to characterize the rough surface thermodynamic properties. Then the validity of the model is verified. Finally, the influence of main parameters on the total normal load and the whole normal stiffness of thermal elasto-plastic contact at the interface is analyzed by contact simulation. The results show that the total normal load of thermal elasto-plastic contact increases with the increases of temperature. The whole normal stiffness of thermal elasto-plastic contact increases with increasing coefficient of linear expansion, scale factor, temperature difference or fractal dimension, but decreases with increasing fractal roughness. This model expands basic theory and applications of traditional models, and can be used to calculate and analyze the contacts when the temperature changes.
A most promising solution to the expansion of spectrum efficiency is cognitive radio (CR) and this expansion is achieved by permitting the licensed frequency bands to be accessed by unlicensed secondary users (SUs) with a lack of interference with licensed primary users (PUs). This utilization of CR networks in the spectrum sensing causes vulnerable attacks like primary user emulation (PUE) attack and here PUs play the role of malicious user and do not permit other users to utilize PUs channel even in their unavailability. On the basis of the traditional single-threshold energy detection algorithm, a novel modified double-threshold energy detector is formulated in the CR network and the detection probability, miss detection probability, probability of false alarm, and their inter-relationship are analyzed. This paper develops a modified double threshold energy detection cooperative spectrum sensing technique to alleviate the PUE attack. Finally, performance-based evaluation is carried out between the proposed and the existing energy detection spectrum sensing method that had no consideration on PUE attack. The resultant of the simulation in MATLAB has revealed that the proposed model has significantly mitigated PUE attack by means of providing outstanding performance.
Many vehicle platoons are interrupted while traveling on roads, especially at urban signalized intersections. One reason for such interruptions is the inability to exchange real-time information between traditional human-driven vehicles and intersection infrastructure. Thus, this paper develops a Markov chain-based model to recognize platoons. A simulation experiment is performed in Vissim based on field data extracted from video recordings to prove the model’s applicability. The videos, recorded with a high-definition camera, contain field driving data from three Tesla vehicles, which can achieve Level 2 autonomous driving. The simulation results show that the recognition rate exceeds 80% when the connected and autonomous vehicle penetration rate is higher than 0.7. Whether a vehicle is upstream or downstream of an intersection also affects the performance of platoon recognition. The platoon recognition model developed in this paper can be used as a signal control input at intersections to reduce the unnecessary interruption of vehicle platoons and improve traffic efficiency.
It is generally believed that intelligent management for sewage treatment plants (STPs) is essential to the sustainable engineering of future smart cities. The core of management lies in the precise prediction of daily volumes of sewage. The generation of sewage is the result of multiple factors from the whole social system. Characterized by strong process abstraction ability, data mining techniques have been viewed as promising prediction methods to realize intelligent STP management. However, existing data mining-based methods for this purpose just focus on a single factor such as an economical or meteorological factor and ignore their collaborative effects. To address this challenge, a deep learning-based intelligent management mechanism for STPs is proposed, to predict business volume. Specifically, the grey relation algorithm (GRA) and gated recursive unit network (GRU) are combined into a prediction model (GRA-GRU). The GRA is utilized to select the factors that have a significant impact on the sewage business volume, and the GRU is set up to output the prediction results. We conducted a large number of experiments to verify the efficiency of the proposed GRA-GRU model.
In order to investigate the stability problem of shield tunnel faces subjected to seismic loading, the pseudo-dynamic method (P-DM) was employed to analyze the seismic effect on the face. Two kinds of failure mechanisms of active collapse and passive extrusion were considered, and a seismic reliability model of shield tunnel faces under multi-failure mode was established. The limit analysis method and the response surface method (RSM) were used together to solve the reliability of shield tunnel faces subjected to seismic action. Comparing with existing results, the results of this work are effective. The effects of seismic load and rock mass strength on the collapse pressure, extrusion pressure and reliability index were discussed, and reasonable ranges of support pressure of shield tunnel faces under seismic action were presented. This method can provide a new idea for solving the shield thrust parameter under the seismic loading.
Beipanjiang Bridge is a long-span concrete arch bridges with stiffened skeleton (CABSS) in China. It has a fixed end arch with the span of 445 m and the rise of 100 m. To evaluate the rationality of the construction sequence and the time-dependent behavior of CABSS, an experimental study of a model bridge was explored. But the measured displacement and stress ratios of arch rib between prototype and model bridge did not subject to linear similarity relation when the time-dependent behavior was considered. So, the three-dimensional finite element models were established, and verified by the measured data. Then, the displacements and stresses of the prototype and model were compared with each other, when the elastic analysis or coupling of temperature and shrinkage, creep effect was considered. Furthermore, a parametric study was studied. The results showed that when the temperature, shrinkage and creep effect of concrete are considered, the finite element analysis results of prototype and model agree well with the measured results. The displacement and stress ratios of prototype and model bridge in construction and bridge completed stage do not present the geometric similarity ratio 7.5 and 1.0, respectively. They are also much influenced by concrete predicting model and variation of temperature.
Fissures play a significant role in predicting the unstable failure of rock mass engineering. For deep rock underground engineering, rock mass containing pre-existing fissures is usually located in triaxial stress state. Therefore, not only pre-existing fissure but also confining pressure affects the failure mechanical behavior of rock material. In this research, the granite specimens containing two non-coplanar open fissures were investigated by a series of conventional triaxial compression tests. First, the effect of bridge angle and confining pressure on strength and deformation characteristics of granite specimens was evaluated. Results show that the triaxial compressive strength, failure axial strain, and crack damage threshold increased nonlinearly with confining pressure. Under high confining pressures, elastic modulus was insensitive to bridge angle. Then, an X-ray micro-CT scanning technique was used to analyze the internal fracture characteristics of granite specimens with respect to various bridge angles and confining pressures. Five typical crack coalescence modes were identified, namely, indirect coalescence, shear coalescence and three types of tensile coalescence. The reconstructed 3-D CT images indicated that under uniaxial or low confining pressures, the bridge angle had a significant effect on crack evolution behavior, while under high confining pressures, shear-dominated failures occurred with the development of anti-wing cracks.
Shield tunneling inevitably passes through a large number of pile foundations in urban areas. Thus, an accurate assessment of tunneling-induced pile displacement and potential damage becomes a critical part of shield construction. This study presents a mechanism research of pile-soil-tunnel interaction through Pasternak-based two-stage analysis method. In the first stage, based on Mindlin’s solution, the soil displacement fields induced by shield thrust force, cutterhead frictions, shield shell frictions and grouting pressure are derived. The analytical solution of three-dimensional soil displacement field is established by introducing Pinto’s three-dimensional volume loss formula, which solves the problems that shield construction factors are not taken into account in Loganathan’s formula and only two-dimensional soil displacement field can be obtained. In the second stage, based on Pasternak’s two-parameter foundation model, the analytical solution of pile displacement induced by shield tunneling in layered soil is derived. A case was found in the project of interval tunnels from Wanjiali Square to Furong District Government of Changsha Metro Line 5, where the shield tunnels were constructed near viaduct piles. The reliability of the analytical solution proposed in this study is verified by comparing with the field measured data and the results of finite element method (FEM). In addition, the comparisons of longitudinal, horizontal and vertical displacements of soil and pile foundation analyzed by the analytical solution and FEM provide corresponding theoretical basis, which has significant engineering guidance for similar projects.
According to the different stress paths, similar model test and PFC simulation test of tunnel surrounding rock are designed to compare the failure mechanisms at macroscopic and mesoscopic scales. The following conclusions are drawn. 1) Excavation unloading will disturb the surrounding rock to form a certain excavation damaged zone. 2) Under the loading path, the stress of surrounding rock failure is 1.500 MPa; under the unloading path with initial stress of 60% σZmax and 100% σZmax, the failure stress is 1.583 and 1.833 MPa respectively in the model test. 3) In terms of the failure mode of rocks under different stress paths, tensile fractures first appear in two sides of the vertical walls; thereafter, the spandrel and arch foot are loosened due to the stress concentration. The fractures gradually coalesce with those occurring in the vertical walls. 4) In the process of excavation unloading, the proportion of shear cracks is 35.3%, and the rock is subject to strong shear effect. The final failure surface is approximately V-shaped. 5) The tangential peak stress on the vertical walls at the free face is the lowest; the vertical walls at the free face show the poorest bearing capacity and are easily subjected to tensile failure.
To optimize the distance between the bells in pile design, this paper reports a series of small scale tests on the uplift capacity of double belled piles embedded in dry dense sand considering different bell space ratios. Finite element modelling is also performed to evaluate the range of soil failure around the piles during pile uplift displacement. Test results show that when bell space ratio is 6 or 8, the uplift capacity reaches the peak value. The upper bell bears more load than the lower one for the piles with bell space ratio less than 6, while the lower bell bears more load than the upper one for the piles with bell space ratio larger than 8.
In order to study the dynamic response of the rail embankment under different speeds and moving load of following vehicles, a model experiment with a ratio of 1:10 is established to test the time history of acceleration and the earth pressure of the embankment at various train speeds. Using the ABAQUS finite element calculation software, a train load is applied through the FORTRAN subroutine, thereby establishing a three-dimensional finite element model with the same size as the model experiment. The data and conclusions of the finite element method model are verified by the model experiment. The model also makes some supplements to the model experiment. The experimental results show that with the increase of speed, the peak acceleration and earth pressure of the embankment also increase. By analyzing the experimental data, it can also be found that the vertical acceleration of the embankment is much greater than the axial acceleration and the lateral acceleration. In addition, the elastic modulus of the soil and the sleeper pitch also have some influence on the acceleration.
Many geotechnical structures, such as the subgrade of high-speed railway, are extremely sensitive to micro deformations. As one of the most commonly used indexes in China to evaluate the potential swelling level of expansive soils, the effectiveness and accuracy of free swelling ratio should be highly required. However, due to the deficiency of geotechnical test regulations for the free swelling ratio test, non-negligible variation difference is often observed among the test results of the same type of soil samples. Thus, a series of laboratory tests are conducted to figure out the influences of soil particle size, initial soil temperature, and wet-dry circulation on the free swelling ratio of expansive soils. The results show that the initial soil temperature exerts an obvious influence on free swelling ratio and a relative weak influence on soil mass of expansive soil with the micro soil particle size (d<0.075 mm), and the correlation becomes unclear when soil particle size is within the range of 0.075 mm≼d<0.500 mm. A larger particle size of expansive soils induces a larger free swelling ratio and soil mass in the soil measuring cup regardless of initial soil temperature. However, the enlarging amplitude decreases as the particle size of expansive soils increases. There is a progressive enlargement of free swelling ratio at the first two wet-dry cycles and then it attenuates gradually when the number of wet-dry cycles further increases.
Cracks easily generate in concrete at early age owing to the shrinkage deformation. CaO-based expansion agent (CEA) and superabsorbent polymers (SAP) have been extensively used for the mitigation of concrete shrinkage. The macroscopic properties of concrete are highly determined by the microstructure. In this study, the influence of CEA and SAP addition on the pore structure evolution of cement paste under different curing temperatures was evaluated via low-field nuclear magnetic resonance spectroscopy. Test results indicated that, in cement paste, a higher CEA content led to a higher porosity and a larger most probable pore diameter (MPPD). Meanwhile, SAP addition increased the porosity and MPPD of CEA cement paste at early age but decreased them after 7 d, and a higher SAP content always brought a higher porosity and MPPD. Furthermore, the addition of SAP led to a lower porosity and MPPD of CEA cement paste than that of plain cement paste after 14 d. Moreover, the porosity and MPPD of CEA cement paste decreased first and subsequently increased as the curing temperature raised.
The early-age thermal cracking easily generates and severely impairs the durability of concrete. The temperature rising inhibitor (TRI) was utilized to regulate the temperature evolution by controlling the cement hydration process. This paper aimed to investigate the pore structure formation and hydration characteristics of cement paste containing TRI by low-field nuclear magnetic resonance. The experiment showed that the T2 peak of cement paste shifted from 7.32 ms to 0.23 ms regardless of TRI addition. But the pattern of pore structure formation was changed with TRI addition, that is, the pore structure formation was delayed, and the pore successively shifted to left in two parts. In addition, TRI addition significantly prolonged the duration of gel pore formation and greatly decreased the increase rate of gel water, which implied that TRI introduction hindered the growth of C-S-H, and subsequently decreased the hydration rates and delayed the main hydration peak. Meanwhile, TRI dissolved and diffused rapidly at 40 °C, delaying the hydration of cement paste seriously. Moreover, TRI brought about the C-S-H nucleation homogeneous and the ion concentration uniform, which might reduce the localized curvature occurring on the sheet of C-S-H, and then decreased the T2 intensity of capillary water and gel water.
The grout-rock interfacial property is one of the key factors associated with the strength of grouted rock masses. In this study, direct shear tests and nanoindentation tests were adopted to investigate the mechanical properties of the grout-rock interface at both the macroscale and microscale. The cohesion of the cement specimens was higher than that of the grout-infilled joint specimens, while their internal friction angle was lower than that of the grout-infilled joint specimens. A “separation method” for identifying the different phases according to the qualitative and quantitative estimations was introduced, and the irregular interfacial transition zone (ITZ) thickness and elastic modulus were estimated. The ITZ thickness of the grout-infilled sandstone specimen ranged from 0 to 30 µm, whereas it was within the range of 10–40 µm for the grout-infilled mudstone specimen. The average elastic modulus of the ITZ in grout-infilled sandstone and mudstone specimens was approximately 58.2% and 54.1% lower than that of the bulk grout, respectively. Regarding the incidence of the rock type, the interlacing between the grout and sandstone was better developed. The ITZ with a higher porosity and lower modulus had a significant effect on the mechanical properties of the grout-infilled specimens.
The adhesion between the mining machine and the deep-sea sediments will significantly affect the driving performance of the mining machine in the deep-sea environment. When the mining machine and the deep-sea sediment interaction simulation was carried out, the accuracy of the particle interaction parameters will directly affect the simulation results. This study proposed a method to systematically calibrate the interaction parameters between deep-sea sediment and grouser through the combination of experiment and simulation. The uniaxial compression test and macro adhesion test and corresponding discrete element numerical simulation were carried out, modifying the contact parameters until the simulation results are close to the experimental results. Then the micro-parameters of the JKR adhesion contact model were back calibrated with the test results, and the contact parameters between soil particle-soil particle and soil particle-metal are calibrated. Besides, the adhesion test shows that the adhesion forces were ranked in the order of 5052<STi80<TA2<TC4 under the same surface roughness, which indicates the aluminum alloy 5052 has the best anti-adhesion performance. The relationship between surface adhesion force and microscopic contact parameters was studied by discrete element numerical simulation, and the result shows that the coefficient of static friction and the coefficient of rolling friction has little effect on adhesion force. While it is mainly affected by the coefficient of restitution and surface energy, the surface adhesion force tends to decrease with the increase of the coefficient of restitution and increase with the growth of surface energy. The obtained parameters of soil particle to soil particle and soil particle to metal affecting the adhesion can contribute to the design optimization for the grouser of mining machines to decrease surface adhesion and enhance its movability and mining efficiency.
An investigation of the effect of simplifying bogie regions on the aerodynamic performance of a high-speed train was carried out by studying four train models, to explore possible ways to optimise the train underbody structure, improve the underbody aerodynamic performance, and reduce the aerodynamic drag. The shear stress transport (SST) k−ω turbulence model was used to study the airflow features of the high-speed train with different bogie regions at Re=2.25×106. The calculated aerodynamic drag and surface pressure were compared with the experimental benchmark of wind tunnel tests. The results show that the SST k−ω model presents high accuracy in predicting the flow fields around the train, and the numerical results closely agree with the experimental data. Compared with the train with simplified bogies, the aerodynamic drag of the train with a smooth surface and the train with enclosed bogie cavities/inter-carriage gaps decreases by 38.2% and 30.3%, respectively, while it increases by 10.8% for the train with cavities but no bogies. Thus, enclosing bogie cavities shows a good capability of aerodynamic drag reduction for a new generation of high-speed trains.
A set of acoustic optimization design methods is established by combining the flow field deterioration theory and the acoustic analogy theory, and applied to the acoustic optimization design of high-speed train snow-plough. The results show that the streamline bodies of the head/tail car are the most important sound sources, respectively, accounting for 23.7% and 33.7% of the total sound energy. Compared with the streamline body of tail head, the streamline body of head car is more biased towards high frequency for the sound source energy. The A-weighted radiated noise of the train body is characterized by broadband sound (mainly in the range of 1–4 kHz) and peak features (especially at 2 kHz). The snow-plough with the maximum expansion length can mitigate the strong peak effect of the sound at 2 kHz, reduce the total sound energy, and show the best acoustic radiation performance in the four schemes. The numerical computation model was checked by the wind tunnel test results.