Numerical Analysis of Delamination Buckling in Composite Cylindrical Shell under Uniform External Pressure: Cohesive Element Method

Nowadays, due to high ratio of strength to weight, composite cylindrical shells are extensively used in a great variety of different industrial applications and under different cases of loads. In this study, the buckling of composite cylindrical shells was examined under uniform external pressure. The buckling analysis of composite cylindrical shells was first done by using theoretical relationships. Doing this, Donnell and improved Donnell equations were employed. Then finite element analysis of composite cylindrical shells was done considering inter-layers delamination. Since delamination is a predominant reason for damage in composite materials, considering different models, the effect of delamination and the factors affecting it (such as the ratio of cylinder length to its cross-section perimeter, delamination size, delamination depth location, and delamination shape) on critical buckling load will be examined. Finally, in the section related to delamination growth, its growth direction and also the effect of embedded delamination shape and size upon delamination growth were examined. The analysis of variance of finite element results show that the area and the depth of delamination with the effectiveness of % 31.92 and % 28.85 have respectively the most effects on critical buckling load. In this study, the 3D modeling of delamination and its growth by using cohesive elements is carried out in ABAQUS software which is the main novelty of this work.