Structural Optimization for Improvement of Train Crashworthiness

Abstract

Despite a recent need for the improvement of train crashworthiness, few design methods have been proposed. To establish it, we tried to introduce the concept of "Crashable body structure" to the design of train bodies in the previous reports. There a train car with crashable zone was modeled by nonlinear spring and mass systems. Here we adopted a closer nonlinear spring and mass model to the real train structure, and propose a method to determine the parameters of the model by solving such an inverse problem as to have the same dynamic properties of the previously optimized simple model. And in comparison with the results of the inverse problems we considered an optimization problem by using the same closer model. Then we solve the problem by two different optimization methods and find strengthes of nonlinear spring in the crashable zones as to minimize the maximum decelerations evaluated in the center of gravity of the car. In several numerical examples, impact decelerations were reduced, and passenger zones could be maintained enough spaces not to injure passengers by the proposed method.