Numerical prediction and experimental analysis of the buckling loads of SMPC cylindrical shells under axial compression

The axial compressive buckling loads of shape memory polymer composite (SMPC) cylindrical shells are very sensitive to geometric imperfections and temperatures, but few studies have been conducted on this phenomenon. In this study, the buckling loads and geometric imperfection sensitivities of SMPC cylindrical shells at different temperatures are determined by means of numerical simulations and experimental analyses. The single perturbation displacement imperfection (SPDI), multiple perturbation displacement imperfection (MPDI) and linear buckling mode imperfection (LBMI) techniques are used to simulate the initial geometric imperfections and calculate the corresponding buckling loads and knock-down factors (KDFs) of SMPC cylindrical shells at different temperatures. In the experimental part, the [0/90/ +/- 45](2) SMPC cylindrical shells are manufactured through the autoclave molding process. The load-bearing capacities at different temperatures are tested and compared with the numerical results. The results demonstrate that the buckling loads of the SMPC cylindrical shell obtained by numerical techniques are sensitive to temperature, while the KDFs are insensitive to temperature. Meanwhile, results indicate that brittle fracture is the main failure mode instead of buckling at low temperature, so there is a risk when using any numerical technique to design SMPC cylindrical shells in low-temperature region. At high temperatures, the SPDI method overestimates the KDFs, while the KDFs calculated by the MPDI and LBMI techniques are in good agreement with the experimental results. However, only the LBMI method can distinguish the influence of temperature on the post-buckling patterns, and the corresponding post-buckling pattern is more consistent with the experiment. In addition, the shape-recovery properties and repeatability of the SMPC cylindrical shells are good.

Automated summary

The buckling loads and geometric imperfections sensitivities of SMPC cylindrical shells at different temperatures were determined through numerical simulations and experimental analyses. The results show that the buckling loads obtained by numerical techniques are sensitive to temperature, while the knock-down factors (KDFs) are not. Brittle fracture is the main failure mode at low temperature, posing a risk for design using numerical techniques in this region. At high temperatures, the single perturbation displacement imperfection (SPDI) method overestimates the KDFs, while the KDFs calculated by the multiple perturbation displacement imperfection (MPDI) and linear buckling mode imperfection (LBMI) techniques are in good agreement with experimental results. The LBMI method is able to distinguish the influence of temperature on post-buckling patterns and has better consistency with experiments.