Experiences with fracture mechanical models in ADINA describing initiation, stable growth, and instability of cracks in compact tension specimens and pressure vessels

Abstract

Our objective is to test the applicability of several J-integral concepts and to obtain more experience with calculations for initiation, stable growth, and instability of cracks in nuclear components. Different numerical methods of calculating the J-integral adopted from de Lorenzi have been implemented in the ADINA program. This paper presents the calculated fracture mechanical behaviour of a compact tension specimen and a precracked pressure vessel both being investigated experimentally. Besides results of crack initiation and stable crack growth a method to determine the transition from stable to unstable crack growth is demonstrated. This method is based on an iteration scheme for the J-integral at each load step, at which a series of crack growth increments with reasonable internal load shift may result. Convergence or divergence of this series predicts stable or unstable crack growth, respectively. Our work on this subject is still in progress.