Optimizing the hole geometry of 2D plates for maximum tensile toughness

A tough material response is important in many fields and can be achieved for brittle materials by adding holes. In this work, a FEM approach is presented to maximize the tensile toughness of pre-cracked 2D plates by adding arbitrarily shaped holes. The initial crack is stopped by a hole and a new crack must initiate at a higher load. This fracture process is predicted using Taylor's Point Method and Griffith's criterion, which is estimated by Configurational Forces. The toughest plate, optimized in a level-set like approach, achieves a tensile toughness 4.5 times higher than a solid plate in all load directions. For comparison, experiments were conducted with selected designs that were laser cut into PMMA sheets.