A novel singular element is presented to evaluate the stress intensity factor (SIF) of the through-thickness crack in this paper. The new element takes into account the special variation of the displacements around the intersection of the crack front and the free surface. The intersection between the crack front and the free surface is named singular point. The proposed element has a vertex which coincides with the singular point. Accurately capturing the distribution of displacements in the vicinity of the singular point is of crucial importance in the implementation of dual boundary element method (DBEM) for the through-thickness crack problems. The element with usual shape functions doesn’t lead to accurate solutions unless extremely fine meshes are used. With these new singular elements, more accurate results for the displacement filed around the singular point and the SIF can be obtained. Numerical examples have demonstrated the accuracy and efficiency of the proposed method.
dual boundary element method, stress intensity factor, through-thickness crack, vertex singularity
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