Distributed damage creates flaw tolerance

A qualitative micromechanical fracture mechanics model is presented that shows how a structure that is sensitive to the presence of a single crack or hole can be rendered flaw tolerant by the presence of an interacting distribution of such flaws. The simple model was inspired by the ductile fracture experienced by the under-designed gusset plates recovered from the I-35W Bridge collapse and by the experimentally measured increase in toughness of concrete damaged by fire.