Effects of Weld Strength Mismatch on J and CTOD Estimation Procedures for SENT Fracture Specimens Based on Plastic Eta-Factors

Abstract

This work focuses on the evaluation procedure to determine the elastic-plastic fracture toughness J-integral and CTOD based upon the η-method for welded SENT fracture specimens with clamped ends. The primary objective is to gain additional understanding on the effect of weld strength mismatch on estimation techniques to determine J and CTOD fracture parameters for a wide range of a/W-ratios and mismatch levels. Very detailed non-linear finite element analyses for plane-strain and 3-D models of SENT fracture specimens with center cracked, square groove welds provide the evolution of load with increased crack mouth opening displacement and load line displacement which are required for the estimation procedure. The results show that levels of weld strength mismatch within the range 10∼20% mismatch do not affect significantly J and CTOD estimation expressions applicable to homogeneous materials. The present analyses, when taken together with previous studies, provide an extensive body of results which serve to determine parameters J and CTOD for different materials using SENT specimens with varying geometries and mismatch levels.