作者：
Wang, ShimingPeng, YongWang, TiantianChe, QuanweiXu, PingCent S Univ
Sch Traff & Transportat Engn Minist Educ Key Lab Traff Safety Track Changsha 410075 Hunan Peoples R China Cent S Univ
State Key Lab High Performance Complex Mfg Changsha 410006 Hunan Peoples R China Cent S Univ
Joint Int Res Lab Key Technol Rail Traff Safety Changsha 410075 Hunan Peoples R China Cent S Univ
Natl & Local Joint Engn Res Ctr Safety Technol Ra Changsha 410075 Hunan Peoples R China
Based on the Simplified Super Folding Element (SSFE) theory, the theoretical prediction of average crushing force (F-avg) for multi-cell thin-walled structures is inferred and a combined five-cellthin-walled structur...
详细信息
Based on the Simplified Super Folding Element (SSFE) theory, the theoretical prediction of average crushing force (F-avg) for multi-cell thin-walled structures is inferred and a combined five-cellthin-walledstructure used in high speed train is proposed and investigated in this paper. The finite element model of the proposed structure and the theoretical prediction are validated by a full scaled impact experiment. Then, parametric studies are performed to evaluate the effects of design variables, including the thickness (t) and the side length (a) of the orthohexagonal cell, on collision responses based on the validated FE model and theoretical prediction. It is found that both specific energy absorption (SEA) and the maximum initial force (F-max) are obviously affected by the design parameters. Particularly, the effect of parameter t on crushing performance is greater than that of parameter a. In further, to minimize the F-max and maximum SEA under the constraint of F-avg a multi-objective robust optimization methodology is adopted. The Optimal Latin Hypercube Design (OLHD) and orthogonal design are combined to perform Design of Experiment (DoE) and dual response surface models (DRSM) are constructed for the optimization. The optimal results of deterministic optimization indicate that the F-avg decreases by 11.07% compared with the original design while the robust optimization optimal result of F-max decreases by 10.01%. However, the robust optimization optimal design is more acceptable considering the robustness, which means the robust optimization is more attractive than deterministic optimization in practical engineering application.
multi-cellstructures are thin-walledstructures having multiple closed cavities in them. They have been established to be good at energy absorption when subjected to high axial compressive loads and crash loads while...
详细信息
Foam-filled thin-walledstructure and multi-cell thin-walled structure both have recently gained attentions for their excellent energy absorption capacity. As an integrator of the above two kinds of thin-walled struct...
详细信息
Foam-filled thin-walledstructure and multi-cell thin-walled structure both have recently gained attentions for their excellent energy absorption capacity. As an integrator of the above two kinds of thin-walledstructures, foam-filled multi-cell thin-walled structure (FMTS) may have extremely excellent energy absorption capacity. This paper firstly investigates the energy absorption characteristics of FMTSs by nonlinear finite element analysis through LS-DYNA. Based on the numerical results, it can be found that the FMTS with nine cells has the most excellent crashworthiness characteristics in our considered cases. Thus, the FMTSs with cell number n=9 are then optimized by adopting a multi-objective particle swarm optimization (MOPSO) algorithm to achieve maximum specific energy absorption (SEA) capacity and minimum peak crushing force (PCF). During the process of multi-objective optimization design (MOD), four kinds of commonly used metamodels, namely polynomial response surface (PRS), radial basis function (RBF), Kriging (KRG) and support vector regression (SVR) for SEA and PCF, are established to reduce the computational cost of crash simulations by the finite element method. In order to-choose the best metamodel for optimization, the accuracies of these four kinds of metamodels are compared by employing the error evaluation indicators of the relative error (RE) and the root mean square error (RMSE). The optimal design of FMTSs with nine cells is an extremely excellent energy absorber and can be used in the future vehicle body. (C) 2013 Elsevier Ltd. All rights reserved.
The sophistication and regularity of natural materials continuously provide inspiration for mankind. Mimicking biological materials to devise advanced energy absorption structures remains grand challenges. Herein, we ...
详细信息
The sophistication and regularity of natural materials continuously provide inspiration for mankind. Mimicking biological materials to devise advanced energy absorption structures remains grand challenges. Herein, we demonstrate a new type of thin-walledmulti-cellstructure, based on the shape and distribution characteristics of bamboo cross-sections. Numerical simulations of the proposed structure under quasi-static axial compression, lateral compression, and three-point bending are conducted through the finite element method. The crashworthiness of the new structure is compared with that of two other classic bamboo-inspired structures and an ordinary circular tube, and the results show that the present has superior specific energy absorption (SEA), compression efficiency, and deformation mode. Besides, our study also investigates the effects of the wall thickness of bamboo-inspired cell elements and the bio-inspired inner shell on the axial crashworthiness of the proposed structure. An optimal design of the bamboo-inspired structure was obtained by particle swarm optimization and the results reveal that, with the initial peak force (IPF)/SEA almost unchanged, the associated performance in SEA/IPF is significantly improved. Along with this guideline, it may provide a meaningful avenue towards the design of new bio-inspired energy absorption structures.
In order to comparatively study effect of foam filling and connecting ribs on dynamic response of multi-cell thin-walled structure (MTS), high velocity (30-70 m/s) mass block impact tests were performed on empty MTS, ...
详细信息
In order to comparatively study effect of foam filling and connecting ribs on dynamic response of multi-cell thin-walled structure (MTS), high velocity (30-70 m/s) mass block impact tests were performed on empty MTS, polyurethane foam (PUR) filled MTS (FMTS) and 2nd order MTS (MTS-2(nd)) with connecting ribs between sub-cells. The dynamic enhancement mechanism of energy absorption of three kinds of thin-walledstructures was discussed based on experimental and numerical results. The results indicate that the dynamic enhancement coefficient (DEC) of the mean crushing force (MCF) is 1.07-1.23 and 1.08-1.33 for empty MTS and FMTS, respectively. The dynamic enhancement of total energy absorption (EA) is 11.4-26.32% for MTS, 13.83-32.52% for FMTS and 4.3-9.68% for MTS-2(nd), compared to the quasi-static compression. The multi-cellularization tends to degenerate the crushing force sensitivity of MTS to the loading rate, while the foam filling increases the sensitivity. The inertia effect is the main reason for the dynamic enhancement of crushing force of thin-walledstructures. The coupling effect of FMTS is related to the dimensions of sub-cells, the impact velocity and the foam strength. The folding pattern and deformation stability of MTS can be improved by filling foams and increasing impact velocity. The multi-cellularization by using connecting ribs is still the most effective method to improve the specific energy absorption of thin-walledstructures, although it causes a size effect and reduces the robustness of deformation modes.
暂无评论