For components with tearing or defects similar to cracks, fracture mechanics has developed criteria for how cracks grow under external stress and ultimately lead to breakage of the component.
Linear-elastic fracture mechanics (LEBM concept)
Linear-elastic fracture mechanics (LEBM concept) allows the quantitative recording of the failure of components with cracks as a result of unstable crack propagation under static load stress, or stable crack propagation under cyclic load stress. This presupposes largely linear-elastic deformation until rupture. The stress intensity concept applies. Based on the model of a plate under tensile stress with a continuous centre crack 2a (Figure 1), the stress field before the crack tip can be described by the stress intensity factor K. For the crack opening type mode 1 according to Figure 1, the stresses can be calculated from the crack tip.