Effect of Fiber Orientation on Initial Postbuckling Behavior and Imperfection Sensitivity of Composite Cylindrical Shells

Abstract

Abstract : Koiter's approach is used to formulate the influence of fiber orientation on the behavior of the cylindrical shell in the initial postbuckling region. Results are presented for three-layer composite cylindrical shells of either glass-epoxy or boron-epoxy subjected to uniform axial compressive load. The results show that the initial postbuckling coefficient that characterizes the extent of imperfection sensitivity of a structure is greater for the glass- epoxy shells than for the boron- epoxy shells. For the glass-epoxy cylinders the slope of the load vs. end-shortening curve in the initial postbuckling region is found to have high negative value, which is not significantly affected by the change in fiber orientation. This suggests that the buckling of a nearly perfect glass-epoxy cylinder under prescribed end-shortening will be catastrophic, regardless of fiber orientation. However, for the boron-epoxy cylinders the negative slope varies with the change in fiber orientation, and whether the failure will be catastrophic or not will depend on the fiber orientation.