Research on the Influence of Multiple Parameters on the Responses of a B-type Subway Train

To obtain improved comprehensive crashworthiness criteria for a B-type subway train,the influence laws of the vehicle design collision weight M and empty stroke D on the train's collision responses were investigated,and multi-objective optimization and decision-making were performed to minimize TS(total compression displacement along the moving train)and TAMA(the overall mean acceleration along the moving train).Firstly,a one-dimensional train collision dynamics model was established and verified by comparing with the results of the finite element model.Secondly,based on the dynamics model,the influence laws of M and D on the collision responses,such as the energy-absorbing devices'displacements and absorbed energy,vehicles'velocity and acceleration,TS,TAMA and the coupling correlation effect were investigated.Then,surrogate models for TS and TAMA were developed using the optimal Latin hypercube method(OLHD)and response surface method(RSM),and multi-objective optimization was conducted using the particle swarm optimization algorithm method(MPOSO).Finally,the entropy method was used to obtain the weight coefficients for TS and TAMA,and multi-objective decision-making was performed.The results indicate that D and M significantly affect the compression displacements and energy absorption of the first three collision interfaces,but have limited impact on the last three collision interfaces.The velocity versus time curves of vehicle M1 and M2 are shifted and parallel with different D.However,the velocity versus time curves of all the vehicles are shifted but gradually divergent with different M.The maximum collision instantaneous accelerations of the vehicles are directly determined by M,but are only slightly affected by D.Under the coupling effect,all concerned collision responses are strongly correlated with M;however,the responses are weakly correlated with D except for the compression displacement at the M2-M3 collision interface and the maximum collision instantaneous acceleration of vehicle M2.The comprehensive crashworthiness criteria of the B-type subway train were significantly improved after multi-objective optimization and decision-making.The research provides more theoretical and engineering applica-tion references for the subway train crashworthiness design.