Objectives:

Develop fatigue life model for woven - roving glass/vinyl ester composite laminates. Model 1 loading is considered.

Approach and Results:

Delamination is a primary failure mode for laminated composite structures. Damage tolerance design concepts require fracture mechanics based total life prediction models. The reserch focused on developing a model that covers the threshold, Paris law, and unstable regimes under model-1 loading for glass/vinyl ester laminates. First, mode -1 fracture test was conducted and established GIR -Da resistance equation. Second, Constant displacement amplitude fatigue tests were conducted and generated da/dN versus GImax/GIR data for R=0.1. Data normalization including the influence of resistance curve was found to best describe the growth rate. The da/dN equation and test data are shown.

Conclusions:

Delamination growth rate equation covering the all threee regimes was developed. The equation can be used to calculate the life for any cyclic loading.