PNNL

Abstract

Predicting the structural performance of a joint requires mechanical characterization of the interface that results from the joining process. Use of the cohesive zone model (CZM) is a popular approach for investigating fractures, seams, and joints in the structures. The CZM requires a cohesive constitutive law, which, in the context of a welded joint, relates the traction at the interface to the separation displacement of the two surfaces. Typical congurations for fracture testing to obtain the parameters for a cohesive law involve assumptions including large weld areas and undisturbed substrate, making those techniques unsuitable for friction stir welded joints. This paper presents an approach of experimentation combined with nite element modeling to determine the cohesive law parameters to mechanically characterize the interface obtained in friction stir welded joints.