Study on Load Reduction Characteristics of Sandwich-Structured Head Cap during High-Speed Water Entry

To address the significant hardening effect and insufficient energy absorption efficiency of traditional monolithic buffer head caps during high-speed water entry of large vessels, this paper proposes a novel sandwich-structured buffer head cap. The structure consists of carbon fiber-reinforced polymer (CFRP) panels combined with a multilayer gradient aluminium foam core. A numerical model of the sandwich structure is developed using the arbitrary Lagrangian-Eulerian (ALE) multiphase coupling algorithm, which is used to analyze its load-reduction mechanism. The results demonstrate that the layered design of the sandwich structure effectively homogenizes plastic deformation through stress concentration. By sacrificing part of the instantaneous acceleration reduction capacity, it achieves a longer structural response time and more uniform load distribution, thereby improving the overall load reduction performance.