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A Novel Model for Describing Rail Weld Irregularities and Predicting Wheel-Rail Forces Using a Machine Learning Approach

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Computer Modeling in engineering & Sciences 2025年第1期142卷 555-577页

作者： Linlin Sun Zihui Wang Shukun Cui Ziquan Yan Weiping Hu Qingchun Meng State Key Laboratory of High-Speed Railway Track system China Academy of Railway Sciences Corporation LimitedBeijing100081China Railway engineering Research Institute China Academy of Railway Sciences Corporation LimitedBeijing100081China School of Aeronautic Science and engineering Beihang UniversityBeijing100191China

Rail weld irregularities are one of the primary excitation sources for vehicle-track interaction dynamics in modern high-speed *** can cause significant wheel-rail dynamic interactions,leading to wheel-rail noise,component damage,and *** researchers have employed the vehicle-track interaction dynamic model to study the dynamic interactions between wheel and rail induced by rail weld geometry ***,the cosine wave model used to simulate rail weld irregularities mainly focuses on the maximum value and neglects the geometric *** this study,novel theoretical models were developed for three categories of rail weld irregularities,based on measurements of the high-speed railway from beijing to *** vertical dynamic forces in the time and frequency domains were compared under different running *** forces generated by the rail weld irregularities that were measured and modeled,respectively,were compared to validate the accuracy of the proposed ***,based on the numerical study,the impact force due to rail weld irrregularity is modeled using an Artificial Neural Network(ANN),and the optimum combination of parameters for this model is *** results showed that the proposed model provided a more accurate wheel/rail dynamic evaluation caused by rail weld irregularities than that established in the *** ANN model used in this paper can effectively predict the impact force due to rail weld irrregularity while reducing the computation time.

关键词： Rail weld irregularity high-speed railway vehicle-track coupled dynamics wheel/rail dynamic vertical force artificial neural networks

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Rock fracture mechanism of buffer blasting with cushion layer at the borehole bottom

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 325-334页

作者： Xinguang Zhu Chenxi Ding Zhe Sui Hong Su Xu Guo School of Civil and Resources engineering University of Science and Technology BeijingBeijing 100083China Key Laboratory for Mechanics in Fluid Solid Coupling systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Mechanics and Civil engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Chemical and Blasting engineering Anhui University of Science and TechnologyHuainan 232001China

This study primarily investigates the rock fracture mechanism of bottom cushion layer blasting and explores the effects of the bottom cushion layer on rock *** involves analyses of the evolution patterns of blasting stress,characteristics of crack distribution,and rock fracture features in the ***,blasting model experiments were carried out using the dynamic caustics principle to investigate the influence of bottom cushion layers and initiation methods on the integrity of the bottom rock *** experimental results indicate that the combined use of bottom cushion layers and inverse initiation effectively protects the integrity of the bottom rock ***,the process of stress wave propagation and dynamic crack propagation in rocks was simulated using the continuum-discontinuum element method(CDEM)and the Landau explosion source model,with varying thicknesses of bottom cushion *** numerical simulation results indicate that with increasing cushion thickness,the absorption of energy generated by the explosion becomes more pronounced,resulting in fewer cracks in the bottom rock *** illustrates the positive role of the cushion layer in protecting the integrity of the bottom rock mass.

关键词： bottom cushion layer blasting crack propagation continuum-discontinuum element method dynamic stress intensity factor

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Force-position collaborative optimization of rope-driven snake manipulator for capturing non-cooperative space targets

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Chinese Journal of Aeronautics 2024年第9期37卷 369-384页

作者： Xiaofeng LI Jian TIAN Cheng WEI Xibin CAO School of Astronautics Harbin Institute of TechnologyHarbin 150001China beijing instiuteof spacecraft system engineering China Academy of Space TechnolgyBeijing 100094Chia

With the rapid development of space activities,non-cooperative space targets increase swiftly,such as failed satellites and upper stages,threating normal spacecrafts *** there are some problems in the capture process,such as excessive collision and fast tumbling of targets,manipulator with redundant Degrees of Freedom(DOFs)can be used to improve the compliance and therefore solve these *** Rope-Driven Snake Manipulator(RDSM)is a combina-tion of hyper-redundant DOFs and better compliance,and therefore it is suitable for capturing *** this paper,a snake manipulator mechanism is designed,and the complete kinematic model and system dynamic model considering RDSM,target and contact is ***,to obtain the configuration of joint with hyper-redundant DOFs,an improved motion dexterity index is pro-posed as the joint motion optimization ***,the force-position collaborative optimization index is designed to adjust active stiffness,and the impedance control method based on the modified index is used to capture the space ***,the proposed force-position collaborative opti-mization method is verified by virtual prototype *** results demonstrate that based on the proposed method,the collision force is reduced by about 25%compared to normal impe-dance control,showing higher safety.

关键词： Capturing non-cooperative spacetargets Rope-driven snakemanipu-lator Force-position collaborative optimization Redundant degrees of free-dom Active stiffness adjustment

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An Optimal Bit-Rate Allocation Algorithm to Improve Transmission Efficiency of Images in Deep Space Exploration

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China Communications 2020年第7期17卷 94-100页

作者： Yong Xu Jionghui Li Xiangyu Lin Fan Bai beijing Institute of spacecraft system engineering Beijing100094

As fixed compression ratio is used in traditional deep space exploration image transmission application,the same compression code rate is allocated to each ***,since the information of each image in a space observation mission is nonuniform,the image with more information will inevitably lead to more compression distortion than the image with less ***,it’s not an efficient way to transmit information in terms of data importance or overall ***,we proposed a combinatorial optimal bit rate allocation algorithm to improve the efficiency of image transmission in space *** from traditional method,the rate-distortion model of wavelet coefficients for each image in a transmission task was built,and under the overall maximum transmission rate constraint,an bit-rate optimal allocation was applied for each image to minimize the overall distortion of a batch of *** proposed algorithm can be widely used in image compression algorithm with embedded code stream characteristics,such as JPEG2000 and *** results shows that in the range of 2.6 to 10 compression ratio,the algorithm can reduce image distortion MSB by 40%~64%at the same overall transmission code rate,which equivalent to improvement of PSNR 3 dB to 5.4 dB.

关键词： JPEG2000 Efficiency distortion

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An optimized run-length based algorithm for sparse remote sensing image labeling

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Defence Technology（防务技术） 2022年第4期18卷 663-677页

作者： Shen-shen Luan Bo-wen Cheng Shuai Jiang Yu-hang Wu Zong-ling Li Ji-yang Yu Institute of spacecraft system engineering Haidian DistrictBeijingChina

Labeling of the connected components is the key operation of the target recognition and segmentation in remote sensing *** conventional connected-component labeling(CCL) algorithms for ordinary optical images are considered time-consuming in processing the remote sensing images because of the larger size.A dynamic run-length based CCL algorithm(Dy RLC) is proposed in this paper for the large size,big granularity sparse remote sensing image,such as space debris images and ship *** addition,the equivalence matrix method is proposed to help design the pre-processing method to accelerate the equivalence labels *** result shows our algorithm outperforms 22.86% on execution time than the other algorithms in space debris image *** proposed algorithm also can be implemented on the field programming logical array(FPGA) to enable the realization of the real-time processing on-board.

关键词： Connected-component labeling Label equivalence resolving Hardware implementation Equivalence matrix On-board processing

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Review of Large spacecraft Deployable Membrane Antenna Structures

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Chinese Journal of Mechanical engineering 2017年第6期30卷 1447-1459页

作者： Zhi-Quan Liu Hui Qiu Xiao Li Shu-Li Yang beijing Institute of spacecraft system engineering China Academy of Space Technology Beijing 100094 China

The demand for large antennas in future space missions has increasingly stimulated the development of deployable membrane antenna structures owing to their light weight and small stowage volume. However, there is little literature providing a comprehensive review and comparison of different membrane antenna structures. Space-borne membrane antenna structures are mainly classified as either parabolic or planar membrane antenna structures. For parabolic membrane antenna structures, there are five deploying and forming methods, including inflation, inflation-rigidization, elastic ribs driven, Shape Memory Polymer （SMP）-inflation, and electrostatic form- ing. The development and detailed comparison of these five methods are presented. Then, properties of membrane materials （including polyester film and polyimide film） for parabolic membrane antennas are compared. Additionally, for planar membrane antenna structures, frame shapes have changed from circular to rectangular, and different ten- sioning systems have emerged successively, including single Miura-Natori, double, and multi-layer tensioning systems. Recent advances in structural configurations, tensioning system design, and dynamic analysis for planar membrane antenna structures are investigated. Finally, future trends for large space membrane antenna structures are pointed out and technical problems are proposed, including design and analysis of membrane structures,materials and processes, membrane packing, surface accuracy stability, and test and verification technology. Through a review of large deployable membrane antenna structures, guidance for space membrane-antenna research and applications is provided.

关键词： Membrane antenna. Parabolic Plane.Tensioning system Dynamics

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Orbit Design Elements of Chang’e 5 Mission

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Space(Science & Technology) 2021年第1期2021卷 28-49页

作者： Zhong-Sheng Wang Zhanfeng Meng Shan Gao Jing Peng beijing Institute of spacecraft system engineering Beijing 100094China

The three key orbit design technologies employed in the Chang’e 5 mission are identified and discussed in this paper:orbit design for lunar orbit rendezvous and docking,orbit design for precision lunar landing and inclination optimization,and orbit design for Moon-to-Earth ***,an overview of the Chang’e 5 mission profile is presented,which is followed by detailed discussions of the three key orbit design technologies,including an introduction of the tracking-based orbit design *** data are provided to demonstrate the correctness of the designs.

关键词： discussions orbit Earth

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On-orbit Space Technology Experiment and Verification Project Outlook of China’s Tiangong Space Station

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Space(Science & Technology) 2023年第1期3卷 416-428页

作者： Zhao Yin Zongpeng Zhu Pei Guo Zhengyi Wang Jinlu Yang Yan Song beijing Institute of spacecraft system engineering Beijing100094China

China’s Tiangong space station has been completed in 2022 to support large-scale multidisciplinary space science research and technology *** a large payload capacity and long operating time,Tiangong space station has many irreplaceable advantages over other spacecraft,such as space transportation,global tracking,on-orbit care for astronauts,and the ability to replace and upgrade experiment *** resources available to the space station and its affiliated spacecraft provide an excellent open verification platform for experimental *** modular design of the intravehicular experiment rack can support different combinations of normal payloads for experiment,and an extravehicular exposed platform is planned to support different sizes of normal payloads for *** paper firstly discusses the mission objectives of China’s Tiangong space station and the development of new space ***,it sorts out the conditions for China’s Tiangong space station to conduct experiments for space *** this basis,a systematic layout for the missions of space technology experiments on China’s Tiangong space station is *** research topics are proposed,i.e.,robotics and autonomous system technology,on-orbit assembly and construction technology for spacecraft,environmental control and life support system technology,new energy and propulsion technology,and new generic technology for *** on the key technologies that restrict the development of China’s future space missions and systems,this study gives an outlook on the on-orbit space technology experiment and verification project for China’s Tiangong space ***,development strategy and suggestions are put forward for China’s space technology.

关键词： payload replace Outlook

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Neural Networks Combined with Importance Sampling Techniques for Reliability Evaluation of Explosive Initiating Device

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Chinese Journal of Aeronautics 2012年第2期25卷 208-215页

作者： GONG Qi ZHANG Jianguo TAN Chunlin WANG Cancan Reliability system engineering Institute Beihang Universitys Beij ing 100191 China beijing lnstitute of spacecraft system engineering Beijing 100081 China

Concerning the issue of high-dimensions and low-failure probabilities including implicit and highly nonlinear limit state function, reliability analysis based on the directional importance sampling in combination with the radial basis function （RBF） neural network is used, and the RBF neural network based on first-order reliability method （FORM） is to approximate the unknown implicit limit state functions and calculate the most probable point （MPP） with iterative algorithm. For good efficiency, based on the ideas that directional sampling reduces dimensionality and importance sampling focuses on the domain contributing to failure probability, the joint probability density function of importance sampling is constructed, and the sampling center is moved to MPP to ensure that more random sample points draw belong to the failure domain and the simulation efficiency is improved. Then the numerical example of initiating explosive devices for rocket booster explosive bolts demonstrates the applicability, versatility and accuracy of the approach compared with other reliability simulation algorithm.

关键词： neural networks importance sampling explosive initiating device reliability nonlinearity

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An equivalent ground thermal test method for single-phase fluid loop space radiator

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Chinese Journal of Aeronautics 2015年第1期28卷 86-92页

作者： Ning Xianwen Wang Yuying Zhang Jiaxun Liu Dongxiao beijing Key Laboratory of Space Thermal Control Technology Beijing Institute of Spacecraft System Engineering (ISSE)

Thermal vacuum test is widely used for the ground validation of spacecraft thermal control system. However, the conduction and convection can be simulated in normal ground pressure environment completely. By the employment of pumped fluid loops＇ thermal control technology on spacecraft, conduction and convection become the main heat transfer behavior between radiator and inside cabin. As long as the heat transfer behavior between radiator and outer space can be equivalently simulated in normal pressure, the thermal vacuum test can be substituted by the normal ground pressure thermal test. In this paper, an equivalent normal pressure thermal test method for the spacecraft single-phase fluid loop radiator is proposed. The heat radiation between radiator and outer space has been equivalently simulated by combination of a group of refrigerators and thermal electrical cooler（TEC） array. By adjusting the heat rejection of each device, the relationship between heat flux and surface temperature of the radiator can be maintained. To verify this method,a validating system has been built up and the experiments have been carried out. The results indicate that the proposed equivalent ground thermal test method can simulate the heat rejection performance of radiator correctly and the temperature error between in-orbit theory value and experiment result of the radiator is less than 0.5 C, except for the equipment startup period. This provides a potential method for the thermal test of space systems especially for extra-large spacecraft which employs single-phase fluid loop radiator as thermal control approach.

关键词： spacecraft rejection orbit conduction branch pumped employment convection outer correctly

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