Improved J and COD estimation by GE/EPRI method in elastic to fully plastic transition zone

It is well known that conventional GE/EPRI method over-estimates the J-integral and crack opening displacement (COD)1COD varies along the crack length. It is zero at the crack tips and maximum at the middle. Throughout this paper, COD denotes the maximum crack opening displacement at the middle of crack length. he elastic to fully plastic transition zone. The present paper investigates this issue and attempts to rectify this error. An improved GE/EPRI method is proposed with the modifications of α (Ramberg–Osgood coefficient) term in the equation of plastic J and COD. The proposed method has been experimentally and numerically validated.