NOTCH TIP DEFORMATION AND J-INTEGRAL ANALYSIS FOR IMPLANT WELDABILITYTEST SPECIMEN

Application of elastic-plastic fracture mechanics techniques to the pr oblems of welded structure toughness evaluation is relatively new. In recent times, a subject of increasing interest is the correlation of R ice's path independent J-integral and its extended formulations to cra ck growth initiation in materials under plastic deformation. The circu mferentially notched implant weldability test specimen is now widely u sed to evaluate the fracture characteristics of weld-base metal compos ites due to its advantages of small size and associated low cost. In t his paper, an incremental finite element analysis, suitably modelled t o admit linear work hardening of materials, has been carried out for t his specimen under monotonic load histories. As a sequel to an earlier work, the domain-independent property of suitable J solutions availab le in the literature have been critically examined from the viewpoint of applying J-criterion to this specimen. Some new results about J and the associated notch tip deformation patterns are obtained here. Also , the role of surface and line contributions under the integral signs in axisymmetric J has been discussed in the context of the present pro blem. Solutions presented demonstrate that the J-integral can be used as a useful notch-tip characterizing parameter for this test specimen.