Study on rollover crashworthiness of a bus with local functional graded thickness sidewall pillar

There are serious traffic accidents and large angle impact on vehicle body when a bus rolls over. In this paper, a novel local functionally graded thickness (LFGT) sidewall pillar and a minimum deformation search (MDS) method are investigated to improve the bus rollover crashworthiness. According to ECE R66 standard, there was most serious deformation of the traditional side column of the bus when the bus rolls over with large angle impact. To reduce the deformation, a LFGT tube is designed to apply to sidewall pillar. In addition, the characteristics of the LFGT tube under large angle impact are analyzed by radial basis function. From the characteristics, a MDS method is proposed to improve the rollover crashworthiness of bus body. Then, the simulation experiments are conducted to validate the influence of LFGT tube on bus rollover crashworthiness. The results show that the MDS method meets the machining accuracy and ensures the computational efficiency for bus rollover collision optimization, and LFGT sidewall pillar optimised by MDS method can improve the rollover crashworthiness of bus body.