Fracture mechanics

Fracture mechanics is the field of solid mechanics concerned with the propagation of cracks in materials under stress. It provides the theoretical framework for predicting whether an existing flaw or crack will grow under applied loads, and it distinguishes between \'\'\'stress intensity\'\'\' — a local measure of the stress field near a crack tip — and the energy required to create new fracture surface. Fracture mechanics bridges the gap between the macroscopic strength of a material and the microscopic processes of bond breaking that govern crack growth. The field was developed initially for metals and aerospace engineering but has been extended to earthquakes through the study of \'\'\'fault rupture\'\'\', where the same principles of energy balance and crack-tip stress fields apply at scales from laboratory specimens to tectonic plates.