Nonlinear buckling strength of out-of-roundness pressure hull

This study employed experiments and numerical simulations to investigate the impact of pressure hulls' degree of out-of-roundness on their buckling strength and buckling modes. In addition, post-buckling simulations were conducted to analyze the post-buckling behavior of the said pressure hull. Regarding numerical simulations for analyzing pressure hull buckling, the common analysis method is to first calculate the eigenvalue and the eigenmodes of buckling and then introduce an appropriate number of eigenmodes based on the initial defect of the structure before conducting a nonlinear buckling simulation. In addition to employing this common nonlinear analysis method (in which ABAQUS was used), this study adopted the PD-5500/33 specification to measure the circularity of the pressure hull for experimentation to confirm that the circularity satisfied the PD-5500/33 specification. Finally, this study compared the differences in nonlinear buckling strength between two numerical models and compared the numerical simulation results with the experimental results. This study verified that by employing the analysis method of eigenmode superpositioning, the buckling and post-buckling behavior of an out-of-roundness pressure hull could be more accurately simulated.