作者机构：
[Xie, Suchao; Feng, Zhejun; Jing, Kunkun; Yang, Shichen; Wang, Hao] Cent South Univ, Key Lab Traff Safety Track, Minist Educ, Changsha 410075, Peoples R China.;[Xie, Suchao; Feng, Zhejun; Jing, Kunkun; Yang, Shichen; Wang, Hao] Cent South Univ, Joint Int Res Lab Key Technol Rail Traff Safety, Changsha 410075, Peoples R China.;[Xie, Suchao; Feng, Zhejun; Jing, Kunkun; Yang, Shichen; Wang, Hao] Cent South Univ, Sch Traff & Transportat Engn, Changsha 410075, Peoples R China.;[Zhou, Hui] Cent South Univ Forestry & Technol, Sch Logist & Transportat, Changsha 410004, Peoples R China.
通讯机构：
[Suchao Xie] K;Key Laboratory of Traffic Safety on Track, Ministry of Education, Central South University, Changsha 410075, China<&wdkj&>Joint International Research Laboratory of Key Technology for Rail Traffic Safety, Central South University, Changsha 410075, China<&wdkj&>School of Traffic & Transportation Engineering, Central South University, Changsha 410075, China
关键词：
Staggered compensation;Multi-tube structure;Induced ring;Load fluctuation;Load curve control
摘要：
To solve the problem of high energy absorption conflicting with small load fluctuation, a multi-tube combined energy absorption structure with induced ring based on the load curve staggered compensation strategy was proposed. The effects of the number, height, and thickness of the induced rings on the load curve trend were investigated by experiment and simulation, and the initial structural parameters suitable for the design of load curve staggered compensation. were determined. Then, the influences of height difference and induced ring distribution on the load curve trend were revealed, and the control method that can make the appropriate difference in each tube load curve was summarized. Moreover, the diagram of the correlation between the key multi-tube combination parameters and the load curve control effect was plotted based on classical theory and the acquired temporal influence. Finally, a multi-tube structure with suitable height difference and variable induction ring distribution was proposed. Compared with the multi-tube structure with the same configuration parameters, the combined structure proposed in this study decreases the initial peak and load fluctuation by 49.45% and 58.93%, respectively, while maintaining a high energy absorption.
通讯机构：
[Lining Xing] S;School of Logistics and Transportation, Central South University of Forestry and Technology, Changsha 410004, China
关键词：
Vehicle routing problem;Multi category goods;Simultaneous pickup and delivery;Split delivery;Improved ant colony algorithm
摘要：
The vehicle routing problem (VRP) with split pick-up and delivery of multi-category goods is characterized by low carbon, demand splitting and simultaneous pick-up and delivery. In view of this, a mathematical model for optimizing vehicle routing with the objective of minimizing the total cost (comprising the fixed cost, carbon emission cost and penalty cost) is established by considering traffic conditions, satisfaction, and energy saving and emission reduction. A new improved ant colony optimization (ACO) algorithm is designed to solve the model and an initial solution is generated with pheromones of vehicles and a heuristic algorithm to ensure the quality of the initial population. A tabu search operator containing five neighborhood operators is constructed to improve the local search ability of the algorithm, and simulated annealing mechanisms are introduced to update global pheromones, so as to increase the diversity of populations. The effectiveness of the model and algorithm proposed in this study is verified through numerical simulation experiments on 18 groups of examples with different scales. The research results not only enrich relevant theories considering problems with demand splitting and the simultaneous pick-up and delivery, but also provide effective theoretical supports for decision making in logistics enterprises in the face of such complex problems.
摘要：
Nomex (R) honeycomb is a widely used composite material. To further improve the mechanical properties of honeycomb and expand the engineering application capability, a Nomex (R) honeycomb with embedded aluminum tubes (NHEAT) was proposed. Tests and simulations show that the NHEAT can improve the mechanical properties and has a beneficial effect on energy absorption. The practical application of the NHEAT in the energy absorption device of railway vehicles was studied, and the energy absorption performance of the device could be improved by 213% and a gradient energy-level response was achieved.
作者机构：
[Zhang, Jing; Xie, SC; Xie, Suchao; Liu, Zinan; Zheng, Shiwei] Cent South Univ, Key Lab Traff Safety Track, Minist Educ, Changsha 410075, Peoples R China.;[Zhang, Jing; Xie, Suchao; Liu, Zinan; Zheng, Shiwei] Cent South Univ, Joint Int Res Lab Key Technol Rail Traff Safety, Changsha 410075, Peoples R China.;[Zhang, Jing; Xie, Suchao; Liu, Zinan; Zheng, Shiwei] Cent South Univ, Sch Traff & Transportat Engn, Changsha 410075, Peoples R China.;[Zhou, Hui] Cent South Univ Forestry & Technol, Sch Logist & Transportat, Changsha 410004, Peoples R China.
通讯机构：
[Xie, SC ] C;Cent South Univ, Key Lab Traff Safety Track, Minist Educ, Changsha 410075, Peoples R China.
关键词：
Stepped wall thickness tube;Combined design;Crashworthiness;Impact force;Finite element analysis
摘要：
A stepped wall circular tube with varying thickness (STVT) and its multi-tube synergistic combination energy absorption structure were developed to address the shortcomings of the high initial peak force of thin-walled metal tubes and the significant load fluctuation of conventional multi-tube combination structures. The STVT was designed with different thickness variations, and its crashworthiness was evaluated numerically and experimentally. An analysis was done on the influences of various characteristics, such as the number of steps and thickness variation, on the crashworthiness of STVTs. Research shows that the STVT with three and four steps has improved crashworthiness. The phase of the curve is significantly influenced by the initial thickness, and for each 0.6 mm difference in step thickness, the peak phase shifts by about 5.5%. In comparison to the combination of four equal-thickness tubes of the same mass, the optimal combination structure optimizes smoothness by 10.67%, energy absorption by 19.52%, crushing force efficiency by 15.30%, and initial crushing force by 20.70%.
通讯机构：
[Hou, F] M;[Wang, RL ] C;Cent South Univ Forestry & Technol, Sch Logist & Transportat, Changsha, Hunan, Peoples R China.;Massey Univ, Sch Math & Computat Sci, Auckland, New Zealand.
关键词：
Multivariate time series forecasting;Global graph;Local graph;Graph structure learning;Information fusion
摘要：
Recent status-of-the-art methods for multivariate time series forecasting can be categorized into graph-based approach and global-local approach. The former approach uses graphs to represent the dependencies among variables and apply graph neural networks to the forecasting problem. The latter approach decomposes the matrix of multivariate time series into global components and local components to capture the shared information across variables. However, both approaches cannot capture the propagation delay of the dependencies among individual variables of a multivariate time series, for example, the congestion at intersection A has delayed effects on the neighboring intersection B. In addition, graph-based forecasting methods cannot capture the shared global tendency across the variables of a multivariate time series; and global -local forecasting methods cannot reflect the nonlinear inter-dependencies among variables of a multivariate time series. In this paper, we propose to combine the advantages of both approaches by integrating Adaptive Global -Local Graph Structure Learning with Gated Recurrent Units (AGLG-GRU). We learn a global graph to represent the shared information across variables. And we learn dynamic local graphs to capture the local randomness and nonlinear dependencies among variables. We apply diffusion convolution and graph convolution operations to global and dynamic local graphs to integrate the information of graphs and update gated recurrent unit for multivariate time series forecasting. The experimental results on seven representative real-world datasets demonstrate that our approach outperforms various existing methods.
期刊：
Mechanics of Advanced Materials and Structures,2023年 ISSN：1537-6494
通讯作者：
Suchao Xie
作者机构：
[Yan, Hongyu; Xie, Suchao; Feng, Zhejun; Yang, Shichen] Cent South Univ, Key Lab Traff Safety Track, Minist Educ, Changsha, Peoples R China.;[Yan, Hongyu; Xie, Suchao; Feng, Zhejun; Yang, Shichen] Cent South Univ, Joint Int Res Lab Key Technol Rail Traff Safety, Changsha, Peoples R China.;[Yan, Hongyu; Xie, Suchao; Feng, Zhejun; Yang, Shichen] Cent South Univ, Sch Traff & Transportat Engn, Changsha, Peoples R China.;[Zhou, Hui] Cent South Univ Forestry & Technol, Sch Logist & Transportat, Changsha, Peoples R China.;[Xie, Suchao] Cent South Univ, Key Lab Traff Safety Track, Minist Educ, Changsha 410075, Peoples R China.
通讯机构：
[Suchao Xie] K;Key Laboratory of Traffic Safety on Track, Ministry of Education, Central South University, Changsha, China<&wdkj&>Joint International Research Laboratory of Key Technology for Rail Traffic Safety, Central South University, Changsha, China<&wdkj&>School of Traffic & Transportation Engineering, Central South University, Changsha, China
摘要：
To achieve the goals of high energy dissipation, a low initial peak, and small load fluctuation, a differentiated combination design of multitube combined structure was developed. Based on a combination of experiment, simulation, and theory, the influences of height and fold distribution on the peak-formation time sequence were investigated, and the combined method of two configurations in the multitube combination was determined. The results show that the initial peak and load fluctuation of the combined structure with variable tube heights and different fold distributions are reduced by 18.42% and 67.77%, respectively, compared with the multitube structure of the same configuration.
