Strength prediction of braided composite plates with lateral holes by a finite element-based point stress criterion

Abstract

Up to now, the notched strengths of composite plates with lateral cutouts cannot be predicted by the point stress criterion because of no analytical solutions available. In this study, this problem is tackled by a finite element-based point stress criterion. In this approach, the stress distribution of a braided composite plate with two semi-circular holes is first obtained by a finite element analysis, in which the experimental notched strength is applied at the boundary of the finite element model. Secondly, the point stress criterion is used to find the characteristic length for each plate with different size of hole by an interpolation of the finite element analysis results. The characteristic length is then expressed as an empirical function of the hole size as well as the width of the plate. Finally, the notched strengths of composite plates are predicted based on the empirical function and the finite element analysis results incorporated with the principle of superposition in elasticity. It is shown that the predicted notched strengths of composite plates with two lateral semi-circular holes by this new methodology agree well with the experimental results.