Multi-scale strength and buckling analysis of 3D woven composite spherical shells subjected to hydrostatic pressure

3D woven composites are considered as the ideal materials for subsea pressure shells owing to their exhibit excellent out-of-plane properties of delamination resistance and compressive damage resistance, which greatly improves the bearing capacity of the structure. This paper presents the influence of the radius-to-thickness ratio and the initial defects on the 3D woven composite spherical shells subjected to external hydrostatic pressure using the multi-scale finite element and theoretical methods. Two kinds of typical 3D woven structures, curved shallow-crossing linking 2.5D, and straight shallow-crossing linking 2.5D, are selected. The results show that the proposed multi-scale finite element method is capable of accurately predicting the strength and buckling behavior of 3D woven composite spherical shells under external hydrostatic pressure loadings, validated by the comparison of theoretical predictions. Furthermore, the fabric structures, radius-to-thickness ratio, and initial defects affect importantly the mechanical behavior of 3D woven composites pressure shells.