Simulation implementation of trajectory and intersections of three-dimensional crack growths with displacement discontinuity method

Abstract

This paper presents some detailed implementation schemes of geometrical evolution of three dimensional crack growth for most scenarios. These include growth of isolated cracks, intersections of crack growth with body surface or another crack at interior or at front edge. The schemes have been implemented in a crack growth simulator FRACOD3D, which is based on displacement discontinuity method (DDM) for stress analysis and implements the geometrical evolution of crack growth by explicitly adding new elements along the crack front. For growth of isolated cracks, there is no need to re-mesh the old part of cracks and thus no need to recalculate the related influence coefficients in the new growth steps. For intersection of growth of a crack with body surface or interior of another crack, minimum re-mesh on the body surface or on the other crack is used by just subdividing three elements. Simulations with early versions of the explicit schemes showed that implementation of the geometrical evolution is very challenging in that the growth could lead to very unsmooth crack and affects the further numerical simulations. Some examples show that the new schemes give smooth growth. It is noted that these schemes can also be employed with other stress analysis methods which represents crack growth by adding new elements along the crack front.