Crashworthiness design and experimental validation of a novel collision post structure for subway cab cars

This paper proposes a novel collision post structure designed to improve the crashworthiness of subway cab cars. The structure provides two innovative features: 1) a simpler connection between the post and the car roof, which gives a more reasonable load transfer path to reduce the stress concentration at the joint; and 2) a stiffness induction design that provides an ideal deformation model to protect the safe space of the cab cars. The novel collision post structure was evaluated with finite element analysis, and a prototype cab car was mechanically tested. The results demonstrate that the deformation response was stable and agreed well with the expected ideal mode. The maximum load was 874.17 kN and the responses remained well above the elastic design load of 334 kN as required by the design specification. In addition, there was no significant tearing failure during the whole test process. Therefore, the novel collision post structure proposed has met the requirements specified in new standard to improve the crashworthiness of subway cab cars. Finally, the energy absorption efficiency and light weight design highlights were also summarized and discussed.