Design and optimization of composite sub-stiffened panels

This study concerns the buckling and post-buckling performance of composite stiffened panels with sub-stiffening structure subject to compression. The buckling response of the composite stiffened panel is first predicted and verified by experimental data available from the literature. Then sub-stiffeners are introduced into the composite stiffened panel. The distribution and stacking sequence of sub-stiffeners are optimized to improve the critical buckling load without adding weight. Further, to investigate the underlying mechanism of sub-stiffeners involved panels deformation and failure during compressive post-buckling process, different skin-stiffener interfacial parameters are considered. Results show that the introduction of sub-stiffeners to composite T-stiffened panel causes a significant improvement of buckling load ( + 122.66%) and induces reestablishment of the stress concentrated zone which leads to different local failure forms with different interfacial properties. In addition, the collapse load of sub-stiffened panel becomes more sensitive to interfacial parameters of skin-stiffener interface due to the presence of sub-stiffeners.