High-Energy Low-Velocity Impact Behavior of Rubber-Coated Sandwich Composite Structure with Buoyancy Material Core: Experimental and Numerical Investigation

The dynamic response and failure of rubber-coated sandwich composite structures with buoyancy material core (RC-BMC-SCS) subjected to high-energy low-velocity impacts were experimentally and numerically investigated. Six types of BMC-SCSs were designed and manufactured, and high-energy low-velocity impact experiments were performed. Based on the Mohr-Coulomb theory and the Ogden hyperelasticity constitutive model, a low-velocity impact finite element analysis model was developed. The results indicate that BMC-SCS damage stages could be divided into: (1) matrix damage, (2) core cracks, (3) debonding and fiber breakage. Three distinct damage stages of the RC-BMC-SCS were revealed: (1) rubber layer energy absorption, (2) core cracks, (3) debonding. The rubber layer can enhance the damage threshold by approximately 100% compared to BMC-SCS. However, rubber energy absorption capacity has an upper limit. Additionally, the larger the curvature of the BMC-SCS, the higher the initial stiffness of the structure and the larger the impact damage area. The results of this study provide valuable insights for the multifunctional design of composite deep-sea marine structures.