Strength Analysis Methods for High Stress Gradient Parts in Composite Structures Ensuring Design Office Requirements

Abstract

Composite structures can be considerably weakened by the introduction of geometrical singularities such as holes or notches, and the strength analysis of these composite parts is thus a major aspect in the design of aeronautical structures. This article proposes to evaluate the maturity of different strength analysis methods dedicated to the prediction of the final failure of open-hole plates. To evaluate the predictive capabilities of the studied failure approaches, tensile tests have been performed on multi-perforated laminated plates with different configurations of perforation, stacking sequences, and two different carbon/epoxy materials. Three different fast computational methods, used in post-treatment of finite-element simulations, are studied: the classical point stress method, the fracture characteristic volume method, and the critical damage area method. Their predictions are compared with the available test results on multi-perforated plates. The limitations of the point stress method are highlighted and the advantages of the two other alternative strength methods are discussed.