Typically, stress intensity factors of embedded cracks and of semi-elliptical surface cracks are computed to within an accuracy of 2%-3% using very few elements (e.g. 18 elements for a semi-elliptical crack's surfaces).
Ease of use
Only the surface requires elements, so the volume remains free of element mesh. Accuracy is easily achieved because there is no (potentially low quality) volume mesh. Cracked surfaces can be meshed either with triangles or with quadrilaterals. Cracks are meshed with quadrilaterals. Compared to finite element meshing, the mesh design work for B3 cracks is minimised.
Crack Element description
Conventional quadratic shape functions (variables: nodal displacements and tractions) with overlaid singular shape functions (variables: crack root node stress intensity factors of modes I, II, and III). The overlaid singular shape functions are global functions which extend across all elements of the crack surface.
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