Abstract:【Objective】In order to better analyze the fatigue life of the high-speed train bogie frame.【Method】dy namic stress measurements are conducted on the fatigue concern measuring points of a certain type of bogie frame,and the data is post-processed. A one-dimensional stress spectrum is compiled using the rain-flow count ing method and the fluctuation center method. By analyzing and calculating the Miner linear cumulative damage model, a nonlinear cumulative damage model considering load interaction and inherent attribute damage, and the Cotern-Dolan nonlinear cumulative damage model, their fatigue life is inferred and compared in three aspects. 【Result】The results show that the difference between the analysis results of the nonlinear model considering in herent damage and the calculation results of the linear model is small, indicating that its nonlinear attribute is not obvious.【Conclusion】The life analysis results of the Cotern-Dolan nonlinear cumulative damage model are overall smaller than other kinds, but the trend is the same, indicating that it is more conservative for fatigue life assessment.

Abstract:【Objective】In order to investigate the static characteristics and lightweight optimization of the rear axle housing of a new pickup truck vehicle,【Method】a research method combining finite element platform sim ulation and bench testing was adopted. Firstly, a finite element model with high computational accuracy was es tablished in Hypermesh software. Secondly, the stress and displacement of the axle shell under full load condi tion were analyzed using ABAQUS simulation platform, and the location of the dangerous cross-section was de termined. Subsequently, the dimensional optimization of the axle shell and the steel plate spring seat and other components was carried out through Optistruct optimization module, and then the reliability of the lightweight optimization was verified through vertical bending static stiffness bench test. Finally, the reliability of light weight optimization was verified by vertical bending static stiffness bench test.【Result】Finite element analysis results show that the dangerous cross-section of the axle housing is located in the housing steel plate spring seat and housing connection with the maximum stress and deformation of 307.20 MPa and 1.440 mm. Size optimiza tion of the axle housing weight decreases from 59.07 kg to 52.55 kg and the weight reduction rate is 11.04%. The stress rises to 310.10 MPa, but it is still less than the yield strength of 45 steel of the axle housing material, which is 355.00 MPa, and the deformation is less than the standard 1.400 mm. The results of the bench test show that the axle housing passes the vertical bending static stiffness test, and conforms to the standard of the automo bile drive axle bench test.【Conclusion】The established finite element model has high accuracy, and the simula tion results are highly close to the results of the bench test. The axle housing optimized by Optistruct has good mechanical behavior performance, and the module has high reliability in axle housing lightweighting.

Abstract:【Objective】The hydraulic manipulator has the characteristics of strong load capacity, fast response speed, wide range of stepless speed regulation, small radiation electromagnetic interference and so on. It is wide ly used in the construction of transportation infrastructure, such as tunnel boring and bridge construction equip ments. This paper aims to summarize the contact operation control methods of hydraulic manipulator, and intro duce the precise coordination control methods of force and position, and finally provide an outlook on future re search directions. 【Method】In practical engineering applications, the hydraulic manipulator often has contact with the external environment, and its contact operation control involves the precise coordinated control of force and position. However, the precise control of force and position requires an accurate dynamic model and accu rate estimation of terminal force. 【Result】Both domestic and international scholars have conducted in-depth re search on the precise coordination control of force and position, achieving significant results in ensuring stable, accurate, and safe contact operations of hydraulic robotic arms. 【Conclusion】Based on these achievements, this paper describes the hydraulic manipulator dynamics modeling, dynamics parameter identification, end contact force estimation methods, and compliance control. Furthermore, it put forward suggestions and prospects for re search.

Abstract:【Objective】To address the issues of imprecise modeling and high computational cost in structural damage detection using the finite element method (FEM), this study proposes a structural health monitoring (SHM) technique that combines the spectral element method (SEM) with the Northern Goshawk Optimization (NGO) algorithm.【Method】Firstly, the spectral element method was used to establish the frequency response function of the structure, which was then applied to construct the objective function for damage localization and detection. This approach divided the damage detection problem into two stages, reducing the optimization dimension and complexity. Secondly, NGO algorithm was introduced to optimize and solve the objective function. Finally, planar truss structure and ASCE Benchmark Structure were used as case studies to compare the damage detection performance of NGO, Particle Swarm Optimization (PSO), and Ant Lion Optimization (ALO) algorithms under various damage cases.【Result】The results show that for low-dimensional and simple structures, NGO, PSO, and ALO algorithms all exhibit good solving capabilities. However, for high-dimensional and large complex structures, NGO demonstrates superior damage detection capability and robustness compared to PSO and ALO.【Conclusion】The improved method enhances the accuracy of numerical modeling in damage detection.

Abstract:【Objective】 To generate a representative time history set of entirely non-stationary seismic motion processes that adhere to the design response spectrum stipulated in the codes for seismic design of highway and urban bridges.【Method】 An evolutionary power spectrum model for entirely non-stationary seismic motion pro cesses was initially formulated by integrating the intensity-frequency modulation function,pertinent to non-sta tionary seismic motion processes,with the Clough-Penzien power spectrum model,applicable to stationary seis mic motion processes. The parameters for this evolutionary power spectrum model were subsequently calibrated in accordance with relevant specifications. According to the spectral representation approach for the simulation of entirely non-stationary seismic motion processes,a MATLAB program was written to generate a representative time history set of the entirely non-stationary seismic motion processes. The fitting error between their mean re sponse spectrum and the code response spectrum was calculated and iteratively corrected. 【Result】 The parame ters of the evolutionary power spectral model for different site classifications and design earthquake groups were derived based on the codes for seismic design of highway and urban bridges. The generated representative seis mic time history set exhibits the typical characteristics of entirely non-stationary seismic motion processes,dem onstrating a satisfactory overall fit between its mean response spectrum and the code response spectrum,with an average relative error within 5%. 【Conclusion】 By employing the evolutionary power spectrum model,a MAT LAB program can be devised to simulate the spectral representation method of entirely non-stationary seismic motion processes. It successfully generated a representative time history set that complied with the requirements of the codes for seismic design of highway and urban bridges. The mean response spectrum of the generated time histories is consistent with the code response spectrum,verifying the effectiveness of the given method and MAT LAB program. This provides reliable seismic inputs essential for the seismic performance evaluation of bridge structures.

Abstract:【Objective】Train wheel is a significant noise source in the rolling noise, and predicting its vibroacou stic behavior involves calculating the large scale acoustic problems. To improve the computational efficiency of wheel sound radiation, this paper introduces the Boundary Element Method with Adaptive Order (BEMAO). 【Method】The sound radiation of the wheel in free space was studied by using the combination of the finite ele ment method and the boundary element method. The BEMAO was used to calculate the sound power radiated by the wheel, the sound pressure at standard measurement point, and the directivity of the wheel acoustic radiation. Comparison was then made with the corresponding results obtained by the conventional boundary element meth od (CBEM) and the fast multipole boundary element method (FMBEM) as well as the computational time.【Result】The sound radiation obtained by three different boundary element methods are basically consistent, but the BEMAOis about 36 times faster than the CBEM, and 11 times than the FMBEM.【Conclusion】The calculation efficiency of the BEMAO is obviously higher than that of other boundary element methods, and remarkable ad vantages and good applicability are shown in studying the sound radiation from the wheel at high frequency. The outcomes of this paper can provide reference for calculations of large scale acoustic problems.

Abstract:【Objective】To promote the informatisation and intelligence of railway engineering operation and maintenance, and to improve the efficiency of maintenance, 【Method】 Based on the secondary development of Revit and Unity3D platform, a railway track engineering operation and maintenance intelligent information plat form is developed. The platform adopts a three-layer structure of data layer, application layer and interface layer, integrates three modules of human-computer interaction, operation and maintenance information management and technical information access, and can realize functions such as AR scanning, BIM model roaming display, animation simulation of complex facilities disassembling and assembling operation, drawing of track geometric waveform, calculation of TQI, access to maintenance records, querying of technical regulations and CAD draw ings, et al., which is of high utility, high portability, and strong operability. It has the features of high practicality, good portability and strong operability. 【Result】 The platform performs well in the field application test of pub lic works, and all functions can run stably, which achieves the expected purpose of research and development. 【Conclusion】 The construction and development of the platform provides a new way of thinking to promote the informatisation and intelligentisation of railway engineering operation and maintenance.

Abstract:【Objective】To improve the accuracy of predicting the severity of traffic accidents and clarify the key in fluencing factors of traffic accident severity.【Method】Fourteen factors related to people, vehicles, roads, and envi ronment that affect traffic accident severity were selected from 885 road traffic accident case data, and a traffic acci dent classification prediction model was constructed using a convolutional neural network with channel attention (CA-CNN). On this basis, the significant influencing factors of traffic accident severity were analyzed using the method of marginal utility.【Result】The results show that compared with the 6 prediction models such as convolu tional neural network (CNN), random forest (RF), NaiveBayes, logistics regression (Logistics), decision table (De cision_table), and bagging algorithm (Bagging), the convolutional neural network model with channel attention fu sion has better overall prediction performance in terms of accuracy, precision, and recall, etc. Among the influenc ing factors of traffic accident severity, the season, whether it is a workday, road type, accident type, illegal lane change, failure to yield, and improper braking have significant effects (p≤0.05).【Conclusion】CA-CNN is an effec tive traffic accident severity prediction model, and the analysis results are helpful in reducing the incidence and se verity of traffic accidents.

Abstract:【Objective】Aiming at the significant degradation of air gap insulation performance of electrical equipment under high-altitude, low-pressure and low-oxygen environments, a study was carried out to character ize the flow propagation under different air pressures and oxygen contents. 【Method】By combining the fluid model with the plasma chemical reaction, a rod-plate electrode structure and a high-altitude low-pressure low oxygen air injection discharge simulation model were constructed to simulate the air injection propagation pro cess under different air pressures and oxygen contents, and to analyze the effects of air pressure and oxygen con tent on the injection propagation speed, electron density, injection channel radius and electric field intensity dis tribution. It analyzed the effects of air pressure and oxygen content on the propagation speed, electron density, channel radius and electric field distribution. 【Result】The results show that,with the reduction of air pressure, the flow injection propagation speed is accelerating, the flow injection head and channel electron density and electric field strength is decreasing trend, the flow injection channel radius on the whole increased; with the reduction of the oxygen content, the flow injection propagation speed is decreasing significantly, the electron densi ty is increasing, while the electric field strength on the whole increases, and the radius of the flow injection chan nel is decreasing. 【Conclusion】The factors of gas pressure and oxygen content have an important influence on the flow injection discharge characteristics and plasma reaction mechanism, which should be considered compre hensively in the actual engineering design.

Abstract:【Objective】To address the significant difference of interior noise between the motor car (M car) and the trailer (T car) during the operation of an urban rail vehicle, this research examines the impact of the motor car's traction drive system on interior noise through a combination of numerical simulation and real-world vehi cle testing. 【Method】Initially, spectral responses and transmission characteristics of the vibration and noise with in and outside the car body of both the motor car and the trailer were analyzed based on test results. Subsequent ly, a full-frequency vehicle interior noise simulation model was developed by integrating the statistical energy method (SEA) and the finite element method (FEA) for numerical simulation purposes. The simulation revealed the distribution patterns of high-frequency airborne sound and low-frequency structural sound within the vehicle. Through computational superposition of structural and airborne sound, comprehensive noise distribution charac teristics across the full frequency band were obtained and compared with corresponding measured data from the rail line. 【Result】The results show that a prominent peak exists in the interior noise of the motor car within the frequency range of 150 to 400 Hz, which corresponds with the vibration peak of the floor structure within the vehi cle. 【Conclusion】The simulation outcomes of the low-frequency structural acoustic model of the vehicle exhibit a high degree of consistency with the actual measured data. The high-frequency noise within the vehicle is pri marily attributed to wheel-rail rolling noise and the airborne acoustic propagation path of the traction system's sound source. The peak noise levels in the motor car are a result of structural vibrations from the traction drive system, which includes the motor and gearbox, being transmitted through the frame and secondary suspension components to the vehicle body structure, leading to increased levels of low-frequency structural noise. These findings may provide some reference for mitigating the impact of the traction drive system on the interior noise of urban rail vehicles.

Abstract:【Objective】To address the challenge of achieving high-precision trajectory tracking control for heavy haul trains under complex track conditions, this paper proposes a multi-mass model for heavy haul trains and a radial basis function neural network sliding mode control (RBFNNSMC) method. 【Method】First, considering the constraints of air brakes and coupler devices, a multi-mass model of the heavy haul trains was established, and the model uncertainty problems caused by human measurement errors and vehicle parameter differences were estimated by using RBFNN. Second, a nonlinear disturbance observer (NDO) was designed to be utilized for re al-time estimation of strong wind, rain, snow, and other external fast time-varying disturbances during the opera tion of trains. Then, a Lyapunov function was designed to prove the stability of the entire system. 【Result】Based on actual track data from the Daqin Railway, speed tracking comparison experiments were conducted using the RBFNNSMC method, PID method, and SMC method. Simulation results show that the speed error of the RBF NNSMC method is within ±0.15 km/h, which is superior to the other two methods. Furthermore, the inclusion of the NDO significantly enhances the RBFNNSMC method's disturbance rejection capability. 【Conclusion】The tracking accuracy of the RBFNNSMC method based on NDO is improved by 27.3% and 28.9% respectively compared to the SMC method in the absence and presence of disturbances, with enhanced robustness as well.

Abstract:【Objective】In order to improve the reconstruction accuracy of the particle velocity and ensure the ac curacy of source identification, 【Method】this paper proposes a compressed equivalent source based-NAH mod el with the sparse acoustic vector sensor array CESM-v by substituting the particle velocity measurement for the traditional pressure measurement and combining the acoustic vector sensor with the sparse sampling and sparse regularization. Several numerical simulations and experiments were carried out to exam the efficiency of the pro posed model. Through multiple analysis of the particle velocity reconstruction, the equivalent source strength re construction and the error calculation, the proposed CESM-v model was compared with the traditional equivalent source based-NAH with particle velocity measurement (ESM-v) and the existed CESM-p model. 【Results】The proposed CESM-v model always performs better than the other two models. Even though using sparse sam pling, the CESM-v model can generate comparable effect of the particle velocity reconstruction to that of tradi tional ESM with adequate sampling, and can give higher and more stable accuracy in particle velocity recon struction than that of the CESM-p model. In short, both simulation and experimental results show that the CESM-v model has better stability and reliability, can obtain good particle velocity reconstruction results with a small number of sampling points, and then the accuracy of sound source identification can be ensured. 【Conclusion】With the robustness of sound field reconstruction, the CESM-v model can be extended to practical projects such as rail transportation for noise source identification and fault diagnosis.

Abstract:To solve the problems of high energy consumption and high pollution of buildings, China has been ac tively promoting the development of green, energy-saving and environmentally friendly wall structures. Among them, as a new type of wall structure, the lattice concrete shear wall structure has multiple functions such as heat preservation, energy saving, sound insulation, fire resistance, light weight bearing, convenient construction and environmental protection, becoming a hot spot of application and research in recent years. This study briefly in troduces the form of lattice concrete wall structure, summarizes the axial compression, corrosion resistance, ther mal, sound insulation, weather resistance, seismic and other properties of lattice concrete wall, and puts forward the problems and deficiencies in the research of lattice concrete wall at present. It shows that the development of lattice concrete wall structure is a major demand for the recycling of building materials and construction waste, which can be used for seismic design of building structures. In the future, its physical properties can be improved from the aspects of new materials, overall structural fire prevention, freeze-thaw in complex environment, etc., and the research on recoverable functionality and high-rise application can be carried out in combination with shock absorption technology to further improve its seismic performance. It provides important scientific basis and technical support for the wide application of lattice concrete walls and their structures.