Evaluation of KII test specimens using J-integral

Abstract

Numerous types of specimens have been proposed recently for studying the mode II fracture toughness KIIC and fatigue crack growth rates under mode II loading. In this paper, three specimens have been subjected to through linear elastic finite element analyses. These are the compact shear specimen proposed by Banks-Sills and Arcan (1982), the NASA LeRC mode II specimen designed by Buzzard et al. (1986) and the compact shear specimen of Richard (1981). The stress intensity factors KI and KII of these three shear specimens have been determined using the path independent J-integral which is decomposed into the symmetric part JI due to mode I loading and the anti-symmetric part JII due to mode II loading. The values of JI, JII and J are obtained by the conventional finite element method. It was found that the Banks-Sills and Arcan compact shear specimen possesses, among other requirements, the smallest ratio KI/KII in comparison with the other two specimens and is therefore more suitable for determining the fracture toughness of materials under mode II loading. © 1994.