The Crash-worthiness Topological Optimization Method Of Leader-follower Joint For Energy Absorption And Re-direction Anti-collision Structure

In the past optimization design of anti-collision structure,only the safety evaluation index must be satisfied.Although the safety evaluation index requires that the crash peak acceleration should be as small as possible in the past optimization design of anti-collision structure,the conflicting requirements has intersection set in the feasible region.With the improvement of the safety regulations,the re-directive evaluation index of anti-collision structure has been added.However,the re-directive evaluation index requires the anti-collision structure to be of extremely high stiffness.Thus lead to the feasible region that simultaneously satisfies the crash acceleration(energy absorption index)and requirement of re-directive(re-directive index)to be empty set.This new conflicting cannot be resolved by the existing optimal designing methods based on mono-layer programming.This paper based on the research of leader-follower joint relationship between energy absorption and re-direction of the anti-collision structure,the quantitative evaluation indexes of energy absorption and re-direction are determined separately.We defined the relationship between the leader and the follower,so the leader-follower joint optimization model is established.According to analysis the solution of the energy absorption and the re-direction optimization problem,it can be seen that this problem cannot be solved from the perspective of numerical optimization.Thus,we combines the crash-worthiness topological optimization method and the leader-follower joint optimization model of anti-collision structure,besides,by introducing the re-directive stiffness compensation method.We are proposed the leader-follower joint of crash-worthiness topological optimization method that make a detailed elaboration.This method solved the topological optimization problem when the anti-collision structure meets the requirements of feasible domain for energy absorption and re-direction is empty set.It will effectively solve the optimization design problem of energy absorption and re-direction anti-collision structure.In order to verify the feasibility of the method,the article discusses and verifies it through two practical engineering problems.On the one hand,it is difficult to balance the problem of both the re-direction in frontal small overlap crash and the energy absorption in frontal impact.As PEV for an example,in order to verify the applicability of the method,both the leader-follower joint of crash-worthiness topological optimization and finite element analysis of the frontal anti-collision were carried out.The results were analyzed qualitatively as follows:the vehicle can be excellently re-directed in 25%small overlap collision and absorb energy prettily in 100%frontal collision,and it is obviously that the method have great significance for improving the passive safety protection performance of vehicle.On the other hand,the safety problem of rear-end collisions of passenger vehicle that need to be solved urgently.After studying the compatibility of the rear-end collision of passenger vehicle and semi-trailer,the anti-collision structure of the rear end of the semi-trailer was optimized using the crash-worthiness topological optimization method of leader-follower joint.The simulation results show that the optimized structure not only can prevent the passenger car drilling under the frontal rear-end collision,but also has superior energy absorption characteristics and excellent crash-worthiness.In addition,the passenger vehicle can be excellently re-direction in small overlap rear-end collision.We can conclude that the optimized structure effectively solved rear-end collision safety problems with different overlapping rates and ensured the safety of occupants.