Exploring various options for improving crashworthiness performance of rail vehicle crash absorbers with diaphragms

Abstract

In this paper, the effects of various design options for improving the crashworthiness performance of a rectangular crash absorber with diaphragms are explored. These design options include (i) optimal tube and diaphragm dimensioning, (ii) optimal diaphragm placement, and (iii) tapering of the crash absorber. The wall thicknesses of the absorber and the diaphragms, the locations of the diaphragms, and the taper angle are taken as design variables to optimize the crashworthiness performance of the absorber. Before the optimization study, a finite element model is generated and validated with experimental results available in the literature. The effect of each design variable on crashworthiness performance is evaluated by solving a series of design optimization problems, and compared with the baseline design. A successive iterative approach is used in this study, where the optimum design variables obtained from a previous optimization problem are used as the initial design of the next optimization problem. Maximum specific energy absorption (SEA) is sought in these optimization problems. A surrogate-based optimization approach is used, where radial basis functions and response surface models are utilized. Optimal tube and diaphragm dimensioning resulted in 59.2% increase, optimum diaphragm placement led to 7.7% additional increase, and tapering resulted in 2.5% further increase in SEA. Overall, the design changes considered in this paper provided 69.4% increase in SEA. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.