FATIGUE GROWTH MODELING OF MIXED-MODE CRACK IN PLANE ELASTIC MEDIA

This paper presents an extension of a displacement discontinuity method with crack-tip elements (a boundary element method) proposed by the author for fatigue crack growth analy-sis in plane elastic media under mixed-mode conditions. The boundary element method consistsof the non-singular displacement discontinuity elements presented by Crouch and Starfield andthe crack-tip displacement discontinuity elements due to the author. In the boundary elementimplementation the left or right crack-tip element is placed locally at the corresponding left orright crack tip on top of the non-singular displacement discontinuity elements that cover the en-tire crack surface and the other boundaries. Crack growth is simulated with an incremental crackextension analysis based on the maximum circumferential stress criterion. In the numerical sim-ulation, for each increment of crack extension, remeshing of existing boundaries is not requiredbecause of an intrinsic feature of the numerical approach. Crack growth is modeled by addingnew boundary elements on the incremental crack extension to the previous crack boundaries. Atthe same time, the element characteristics of some related elements are adjusted according tothe manner in which the boundary element method is implemented. As an example, the fatiguegrowth process of cracks emanating from a circular hole in a plane elastic plate is simulated usingthe numerical simulation approach.