This paper presents in detail the application of an energy method to describe a class of delamination crack growth problems found in polymer-based composite laminates. The energy method is derived from the general concepts of classical fracture mechanics. When used judiciously and with proper interpretation of the physical factors pertinent to the crack growth process at the lamina(ply) level, the method describes well delamination growth behavior in laminates that are subjected to monotonically (static) or cyclically(fatigue) applied loads or to both. Both could be in tension or in compression.

The basic method can be used to describe not only one-dimensional delamination growth (for example, free edge delamination) but also two-dimensional delamination growth (contoured delamination). Laboratory test results using laminates made of an AS-3501-06 graphite epoxy system are presented along with analytically predicted results. Excellent correlations between analytical and experimental results are obtained.