An algorithm to generate quadrilateral or triangular element surface meshes in arbitrary domains with applications to crack propagation

Abstract

AbstractA new hybrid algorithm for automatically generating either an all‐quadrilateral or an all‐triangular element mesh within an arbitrarily shaped domain is described. The input consists of one or more closed loops of straight‐line segments that bound the domain. Internal mesh density is inferred from the boundary density using a recursive spatial decomposition (quadtree) procedure. All‐triangular element meshes are generated using a boundary contraction procedure. All‐quadrilateral element meshes are generated by modifying the boundary contraction procedure to produce a mixed element mesh at half the density of the final mesh and then applying a polygon‐splitting procedure. The final meshes exhibit good transitioning properties and are compatible with the given boundary segments which are not altered. The algorithm can support discrete crack growth simulation wherein each step of crack growth results in an arbitrarily shaped region of elements deleted about each crack tip. The algorithm is described and examples of the generated meshes are provided for a representative selection of cracked and uncracked structures.