On the development of a general theory of the mechanics of tensile fracture of fibre reinforced materials

Abstract

A general analysis of the tensile fracture of fibre reinforced composites is proposed. It is applied here to the failure of laminates containing a notch or cut out of arbitrary size and also to the failure of a nominally undamaged unidirectional composite. Comparisons are made with published experimental data. In the case of laminates the model predicts the “hole size effect”, the development of damage zones and the effect of various factors on notch sensitivity. The tensile strengths of unnotched unidirectional composites are also correctly predicted. The computation is based on the general form of the strain field surrounding a crack bridged by reinforcing members and has previously been applied in a modified form to transverse ply cracking in laminates. Since the analysis is based on a simplified physical description of the mechanics of fracture some insight is provided into the ways in which the mechanical characteristics of a composite system influence the failure processes and the stress levels at which they occur.