EFFECT OF STEP SPACING ON DELAMINATION OF TAPERED LAMINATES

Tapered laminates often fail by delamination. Studies have been made by many investigators to establish mathematical models for predicting the strength of tapered laminates. However, one area of importance in this problem that has not received adequate attention is the effect of the distance between neighbouring steps. This problem is studied both experimentally and theoretically for unidirectional glass-fibre/epoxy material. It is shown that when the step spacing is small, the step spacing has a significant effect on the delamination stress. However, when the spacing is greater than a certain value, the effect is negligible. A simple formula for estimating this distance is given and shown to be consistent with experimental results.