Optimal design of metallic sandwich tubes with prismatic cores to internal moving shock load

Abstract

Prismatic metallic sandwich tubes subject to internal moving shock loads are optimally designed for minimum weight. The stretching-dominated core topologies are considered, and the effective stiffness matrices of prismatic cores are predicted via homogenization procedure. Failure mechanisms are estimated on the basis of structural responses that are obtained by using the multi-layer sandwich model considering the shear deformation and compressibility of the core. In present study, the constraint functions on failure mechanisms are not explicit expressions, leading to the discontinuity of the optimization problem; hence, the genetic algorithm is invoked. The optimum parameters and minimum weight are evaluated. Meanwhile, the optimal designs are validated by finite element simulations. The results demonstrate that the rectangular core is preferred among three core topologies, and the rectangular core with four layers of cells is most weight-efficient at high load indices, but one layer at lower load indices. The effect of the number of unit cells in circumferential direction on the minimum weight design is slight. In addition, the optimal sandwich tubes are inferior to the optimal monolithic tubes at selected load indices, from a weight-efficiency standpoint, attributed to the fact that face yielding induced by circumferential tension primarily dominates the minimum weight design.