The increasing use of carbon fiber-reinforced polymer (CFRP) shells in deep-sea environments calls for a clearer understanding of their mechanical response and failure under complex stress states, particularly biaxial compression. To address this need, laminate and cylindrical-shell specimens with a stacking sequence of 90°/90°/90°/20°/−20°ns were designed and tested under uniaxial compression, biaxial compression, and hydrostatic pressure. Three-dimensional user material subroutines based on Fortran were developed for the maximum stress/strain, Tsai–Wu, Rationalized Tsai–Wu (R-Tsai–Wu), Hashin, and Shokrieh failure criteria to simulate the failure behavior of CFRP laminates under biaxial compression. The experimental and numerical results show that the biaxial compressive ultimate strength of CFRP is significantly lower than the corresponding uniaxial compressive strength in each loading direction. The Hashin criterion exhibited the highest predictive accuracy, with an error of only 2.6% for the strength in the 90° direction and 15.1% for the 0° direction under equal-displacement biaxial compression. The simulated failure pressure for the cylindrical shell was 20.75 MPa, differing by only 5.7% from the experimentally measured value of 22 MPa. This work provides an important experimental basis and reference for the selection of failure criteria in the strength design and evaluation of CFRP composite shells in deep-sea environments.
Zhou et al. (Sat,) studied this question.