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 "Crushable body structure" to the design of train bodies in the past reports. There a train car with crushable zone was modeled by nonlinear spring and mass systems. Here we adopted a closer nonlinear spring and mass model to the real structure, and propose a method to determine the optimized structure of the train. We also considered an optimization problem by using the same model. Then we solve the problem by two different optimization methods and find strengths of nonlinear spring in the crushable zones as to minimize the maximum decelerations evaluated in the center of the gravity of the train. We use 1-car train model and 2-cars train model to compare the results. In several numerical examples, it is seen impact decelerations were reduced, and passenger zones could be maintained enough spaces not to injure passengers by the proposed method.
