Papers by Author: Xiao Qi Chen

Abstract: To realize the lightweight structure, a car body frame conceptual design of a mini electric vehicle was performed with topology optimization and size optimization. Topology optimization was used to search load paths and size optimization was applied to model a simplified structure. Static stiffness, crash safety and free vibration conditions were considered simultaneously in both of the optimization phases. Due to the feature of conceptual design, crashworthiness cases were regarded as static stiffness ones with inertia relief analysis for a linear equivalent. The objective function in multi-objective topology optimization was defined by Compromise Programming Method in OptiStruct. Because of the characteristic of the geometry and the manufacturing constraints of profiles, the design variables in size optimization were defined as both continuous and discrete variables. The resultant structure outperforms the original one in many structure responses and most significantly, it reduces weight by 36%, which demonstrates the efficiency of the proposed method.

Abstract: According to the experience of traffic accident investigation over the years, the pointer of some crashed vehicles’ speedometer will stay in one place because of collision spread or heavily vibration, which may indicate the vehicle collision speed. However, the correlation between the residual speed value and actual vehicle collision speed still remains to be examined. For the practical needs of traffic accident reconstruction, this research work is carried out. Based on the principles of traditional speedometers, vehicle impact mechanics and failure mechanism, the damage and failure mode of speedometer in collision are studied. Through the statistics of 15 real traffic accident cases, the features and law about the pointer information of damaged speedometers are obtained initially. As an example, one of these cases is analyzed and calculated to verify the assumption. The availability of the mark information on the indicated place of speedometer after accidents (i.e. the correlation between the speed value of pointers and actual vehicle collision speed) is discussed, which can provide effective means and references for accident reconstruction and vehicle speed identification.