Strain-Energy Release Rate Analysis of Cyclic Delamination Growth in Compressively Loaded Laminates

: In composite structures subjected to compression loads, delaminations can cause localized buckling (fig. 1). High interlaminar stresses at the edges of the buckled region often lead to cyclic delamination growth (herein referred to as instability-related delamination growth). The objective of this paper is to investigate the mechanism of instability-related delamination growth. Figure 1 shows the configuration used in the study--a laminate with a 'through-width' delamination. This configuration was selected because it is perhaps the simplest configuration that exhibits instability-related delamination growth. Goals of the investigation were: (1) to develop and use an approximate superposition stress analysis to explain how various geometric, material, and load parameters affect interlaminar stresses, (2) to determine the delamination growth behaviors predicted by several different criteria based on strain energy release rates, and (3) to compare analytical calculations with experimental observations to determine the applicability of each growth criterion. (MM)