Strain energy release rate
= Strain energy release rate
{title2=$G$}
The reduction in a mechanical system's potential energy per incremental crack area under specified loading conditions. In small-scale-yielding linear elasticity, mode-I <plane strain> gives $G=K_I^2/E'$ with $E'=E/(1-\nu^2)$. The critical value includes the dissipative processes associated with crack advance.