An Imperfection Sensitivity Analysis on Buckling of Laminated Composite Cylindrical Shells

Buckling is an instability problem which occurs under compressive forces on slender structures, and it happens suddenly without warning. Therefore, calculating correct critical buckling load is important for thin walled structures. Including imperfection in the analysis is very important since buckling loads with imperfection are far lower than the buckling loads obtained by assuming that they are perfect. Ignoring the initial imperfections may cause unexpected failures. It is possible to classify the imperfections as geometric, material or loading. Among them, the geometric imperfection has the highest effect on the critical buckling load. In this study, the influence of geometric imperfection on the buckling of axially loaded composite cylindrical structures is investigated. A parametric study is conducted to determine how the imperfection sensitivity can vary with the length to diameter ratio, stacking sequence, and the shape of the imperfection. For this purpose, Finite Element Analyses (FEA) are implemented by using a commercial FEM code, ABAQUS.