Structural optimisation for the collapse zone of a railway vehicle

The collapse zone is a critical component of railway vehicle, which is designed with multiple functions, i.e., supporting neighbouring components and attached equipment in its normal operation and absorbing impact energy in a crash accident. However, there is a lack of systematic study on the design of the collapse zone based on the strategy of topological and size configurations. To make full use of the material, topology optimisation for conceptual design is conducted under concurrent static and crash loads. The importance of assigning dynamic weighting to each loading case has been proved to avoid the existence of a dominant case. The topological results show that the load transferring paths (i.e., the space where materials are distributed to) are in the longitudinal direction. In the detailed design, a revised model is created, which addresses structural and manufacturability concerns. To optimise the thickness assignment, the desirability approach is combined with the discrete optimisation method. The final design is obtained and compared with the currently-used collapse zone structure. The radar map of crashworthiness indicators shows that the overall crashing performance of the optimised structure is superior to the traditional one.