Crack opening displacement approach to assess multiaxial low cycle fatigue

This paper proposes universal J-integral range for correlating multiaxial low cycle fatigue lives. The universal J-integral range is a function of Young’s modulus, yield stress, strain multiaxiality and specimen geometry, so it is not necessary to conduct multiaxial low cycle fatigue experiments to determine the universal J-integral range. The universal J-integral range was derived from J-integral and the equivalent strain based on crack opening displacement (COD strain) for a multiaxially loaded mode I crack. The COD strain is a parameter expressing the strain intensity ahead of a mode I crack subjected to multiaxial stresses and strains. The universal J-integral range successfully correlated the multiaxial low cycle fatigue lives of type 304 stainless steel, Cr–Mo–V steel, Inconel 738 LC nickel base superalloy and 63Sn–37Pb eutectic solder universally within a factor of three band independent on the material.