Notched Strength Prediction of Holed Woven Glass/Epoxy Laminates with Tan's Models

Abstract

The point strength model and the minimal strength model proposed by Tan were applied to predict the notched strength of three woven Glass/Epoxy laminates (two orthotropic and one quasi-isotropic) under monotonic uniaxial loading. In the two models, the stress field around the hole for a finite-width notched laminate was expressed by a numerical solution which was determined essentially by the characteristic roots of the notched laminate, and was anew determined in each rigidity degradation step because the rigidity and compliance matrices of the laminate (which give the coefficients in the characteristic equation) vary with the loading due to damages. The characteristic dimensions defined and adopted in the two models were also anew determined in each critical ply. The results show that the strength reduction factor (SRF) curves as a function of hole diameters determined with the characteristic dimensions of the ± 45 ° plies for the laminates studied can give much better notched-strength prediction results than with those of the 900 plies especially for the orthotropic laminates. The damage mechanisms in the woven laminates are very different from those in non-woven laminates.