It is a challenge to efficiently and accurately predict train dynamic responses during complex collisions. In this paper, a novel numerical simplification method for high-speed rail vehicles during complex impact configurations is proposed. The central section of high-speed rail vehicles is a sandwich corrugated hollow double-shell structure. Starting with a baseline detailed finite element (FE) model of a high-speed train, the central section was first simplified as a solid single-shell structure. A parametric study with various simplification thickness ratios of the simplified FE rail vehicle model in different longitudinal rigid-wall collisions and lateral rigid-cylinder impacts was then performed using LS-DYNA. Furthermore, a correlation and analysis (CORA) objective rating method was used to evaluate the related responses between the simplified and detailed baseline FE rail vehicle models. The results demonstrate that the simplified FE model could effectively predict the rail vehicle impact responses. The displacement and impact force time histories of the simplified vehicle model with a thickness ratio of 0.38 matched closely with the results of the baseline detailed FE model under both longitudinal and lateral impacts (total combined CORA rating score: 93%). The rail vehicle impact deformations of the simplified vehicle model were similar to those of the baseline detailed model. The application of the simplified vehicle FE model substantially reduced the computational time (approximately 55% reduction). This work provides a solid basis for efficiently exploring train impact responses in complex collisions, and will be especially useful for train occupant injury assessment.

This paper proposed a multi-layered bi-directionally corrugated plates structure (BCPS) for energy absorption. Quasi-static compression experiments and finite element method (FEM) were used to investigate the crushing performance of the multi-layered BCPS. The results showed that the multi-layered BCPS had very small initial peak crushing force, and the fluctuation of force was very small during the whole compression process. These characteristics made the multi-layered BCPS more advantageous in crashworthiness than traditional structures. It was also found that the crushing performance of the multi-layered BCPS was very sensitive to the geometrical parameters, such as the number of the cellular structures along the width n_c, the number of plates n_l, and the ratio of width of small square w_s to width of big square w_b of the pyramid cell η. Therefore, parameters optimization was carried out using the Multi-Objective Genetic Algorithm to find the best geometrical configuration of the structure. After optimization, the optimum parameters n_c = 5, n_l = 11 and η = 0.38 was obtained. The specific energy absorption increased by 143.76% compared with the initial configuration.

Formation of residual stress, as results of machining process, is a familiar fact. One question that needs to be raised is how to know the actual value of residual stress and its distribution in work. In this paper, we explore a detecting-system based on ultrasonic and Wi-Fi to measure residual stress in materials expediently. By using different frequencies and normal transducers, residual stresses in different depths and surface of a U-shaped block, designed with the states of opening and closing, are measured by cross-correlation algorithm about difference of times L _CR wave spreading. The Finite Element method analyzing the U-shaped block provides an object contrast to verify the correctness of results detected by the detecting system. We evaluate significantly the actual value of residual stress by comparing a position existing residual stress with another position without residual stress. The second contribution of the paper is to build a system about calibrating the results of residual stress measured by ultrasonic.