Optimization and collision failure analysis of ship sandwich structure based on negative Poisson's ratio conceptual design: Failure mechanism and experimental verification

With the increasing demand for lightweight and high impact resistance of ships, negative Poisson's ratio structure shows great potential in ship side protection design. A titanium alloy sandwich plate based on concave hexagonal negative Poisson's ratio element is proposed to meet the crashworthiness requirements of ship side protection structure. Through quasi-static compression numerical simulation and theoretical analysis, the concave hexagonal structure with the best energy absorption characteristics is selected from four typical negative Poisson's ratio configurations. In order to efficiently solve the high-dimensional nonlinear problem in ship structure optimization, a back propagation neural network proxy model optimized by crown porcupine optimization algorithm is constructed by combining the optimal Latin hypercube experimental design. The whale optimization algorithm is used for multi-objective optimization, aiming at maximizing energy absorption and minimizing platform quality, and the optimal structural parameters are obtained. Finally, LS-DYNA is used to simulate and verify the low-speed collision of titanium alloy ship structure with negative Poisson's ratio. The results show that compared with the traditional titanium alloy stiffened plate, the negative Poisson's ratio plate can reduce the weight by about 28.50% while maintaining the same protective performance. This article provides a new solution and theoretical basis for the design of high performance and lightweight ship protective structure.