A numerical investigation on ultimate strength of marine sandwich composites under combined biaxial compression and lateral pressure

With the development of large-scale and light-weight ships, sandwich composites are increasingly used in hull structures because of their advantages of light weight, excellent mechanical properties, and corrosion resistance. Due to the synergistic effect among materials, sandwich composites overcome the shortcomings of single materials and become the main components in composite ship. In actual composite ship, sandwich composites are subjected to the combination of in-plane and out-of-plane loads. The ultimate strengths and failure modes of sandwich composites under combined load cases are complex and variable since the great difference in performance between component materials and material progressive damage of composite. In this paper, progressive failure analysis method and bi-modulus model are used to analyze the ultimate strength and failure modes of sandwich composites under biaxial compressive loads and lateral pressure. 24 cases are simulated with varied load combinations. The results are presented and discussed in terms of force end-shortening curves, ultimate strength, and failure modes. The numerical results indicate that loading sequence affects the progressive failure process of composite but has little influence on the ultimate strength of sandwich and lateral pressure would reduce the ultimate load-carrying capacity. Compared to uniaxial load, the failure modes under combined loads are more complex and variable and are Significantly influenced by the load combinations. The results of this investigation can be helpful for understanding combined loads’ influence on the ultimate strengths and failure modes of marine sandwich composite and contribute to advancing the feasibility analysis, safety assessment, structural design, and optimization of composite materials for hull structures.