NEAR-TIP FIELD CHARACTERIZATION AND J-INTEGRAL EVALUATION FOR NONPROPORTIONAL LOADS

The J-integral is calculated numerically using the domain integral method and a contour integral according to the definition of the J. It was conjectured that the methods could give conflicting results for nonproportional loads. It is found, however, that both methods give satisfactory results conforming even for highly nonproportional loads. In plane strain, the near-tip field could successfully be characterized by a two-parameter description according to the J-Q theory. Remotely applied nonproportional loads corresponded to different paths in the J-Q space. This was demonstrated in the range of small-scale yielding up to fully yielded situations.