Crack tip opening displacement

Crack tip opening displacement (CTOD) is the displacement at the original crack tip and the 90° intercept. Crack tip opening displacement (CTOD) is the displacement at the original crack tip and the 90° intercept. LEFM (Linear elastic fracture mechanics) is not valid. This assumption was proven when a unique relationship between CTOD and the J integral was established. CTOD can be expressed in terms of K as K 2 σ y E m {displaystyle {frac {K^{2}}{sigma _{y}Em}}} that in this case m=1 for plane stress and 2 for plane strain. For Linear Elastic Conditions, the relationship between CTOD and G is given by an equation between CTOD and J in the limit of Small-Scale Yielding.