On the determination of crack initiation directions under mixed mode loading

Abstract

An important issue in the mechanics of multilayered structures is the knowledge of local stress fields. Light-weight heterogeneous structures with crack- or notch-like discontinuities possess great danger of stress concentration and possible crack initiation leading to failure. In the present study, computational procedure, namely the finite element method, has been used to analyze bimaterial medium with various notch opening angles under arbitrary loading conditions. The prediction of the direction of crack initiation is important for wedge type constructions to gather a first hand knowledge of a potential damage zones which may undermine the integrity of the structure as a whole. The application of computational procedure to predict potential directions of crack initiation gives the flexibility required for different structural configurations, lamina orientations and incorporation of various boundary conditions. Superposition of various external loads to simulate pure mode I, mode II and mixed mode cases can also be carried out with excellent results in computational procedure. All the analysis results are based on the hypothesis of Erdogan and Sih. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)