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.

3D编织复合材料由于具有出色的抗分层性和抗压缩破坏性的平面外特性，因此被认为是海底压力壳的理想材料，从而极大地提高了结构的承载能力。本文利用多尺度有限元和理论方法，研究了半径-厚度比和初始缺陷对3D编织复合球形壳承受外部静水压力的影响。选择了两种典型的3D编织结构：弯曲的浅交叉链接2.5D和直的浅交叉链接2.5D。结果表明，所提出的多尺度有限元方法能够准确预测外部静水压力载荷下3D编织复合球形壳的强度和屈曲行为，并通过理论预测的比较得到了验证。此外，织物结构，半径/厚度比和初始缺陷会严重影响3D机织复合材料压力壳的机械性能。