Crashworthiness optimization method for sandwich plate structure under impact loading

Abstract

Energy absorbing structures like sandwich plate structure (SPS) are lightweight, fuel economical and environmentally friendly for lightweight ship design. Aimed to improve passive safety protection, a composite SPS is designed for better crashworthiness of ship in this paper. Compared with the replaced stiffened plate, the energy absorption performance of designed SPS is significantly improved. A fast and efficient three-stage combinatorial optimization method, synthesized by optimal Latin-hypercube design (OLHD) method, radial basis function (RBF) surrogate model and multi-objective particle swarm optimization (MOPSO) evolutionary algorithm, is proposed to reduce the number of collision FE simulations required and improve the efficiency of crashworthiness optimization of SPS. Based on sample points obtained from OLHD, the approximation relationships between the crashworthiness indexes, the energy absorbption (EA) and the peak crushing force (PCF), and the structure design variables is formulated using RBF surrogate models. The MOPSO algorithm is applied to multi-objective optimization process to obtain the maximum EA and minimum PCF. Finally the Pareto optimal front of SPS is obtained. The results allow us to determine the structure with the best crashworthiness. SPS and optimization methods proposed are expected to provide inspiration for improving the safety of protective structures and lightweight composite ships.