Buckling of composite laminates with multiple delaminations: Part II experiments

Abstract

This paper focus on the experimental study of the buckling of composite laminates with multiple delaminations, as a succession to the theoretical and numerical studies in Part I. Test specimens containing delaminations of different length and different depth were fabricated by embedding Teflon plastic film using hot pressing machine. Compressive tests were carried out to investigate the influence of the delamination conditions on the buckling and post-buckling performances of the composite laminates. It was found that a surface delamination deteriorates the stiffness of the laminate less than a deep-buried delamination does, while iso-thickness-spaced multiple delaminations damage the stiffness severely compared with non-equal-thickness-spaced delamination for the same number of delamination. In general the larger the length and the number of delamination, the smaller the buckling load. Nevertheless, when the total length and the number of the delamination are fixed, the laminates containing multiple delaminations of equal length have a higher buckling load. Furthermore, it was observed that regardless of the number of delamination, all laminates are suffered to a global buckling. Local buckling does not occur until global buckling occurs. The experimental results justify the theoretical prediction; thereby confirm the correctness and validity of the theoretical approach proposed in Part I.