Reliable J-values - numerical aspects of the path-dependence of the J-integral in incremental plasticity

The determination of reliable J-values in structural analyses by the finite element method for elastic-plastic material behaviour is addressed. A survey over the theoretical background of the J-integral is given, possibilities and restrictions of application in elastic-plastic fracture mechanics are pointed out, and the calculation by the finite element method with special reference to ABAQUS is addressed in detail. In particular, the problem of path-dependence in incremental plasticity is discussed. It is shown that only a far-field value of J is uniquely defined, physically significant and in accordance with the results of respective experimental standards.