Two- and three-dimensional elastic-plastic stress analysis for a double edge notched tension specimen

Abstract

This paper describes an elastic-plastic stress analysis for a double edge notched tension specimen, a specimen used for the determination of the microscopic cleavage fracture stress. The analysis was performed numerically using the finite element method. First, a study of the finite element modelling is presented in order to demonstrate the requirements on a three-dimensional finite element structure leading to accurate stress distributions in the whole specimen. On the other hand possible restrictions are shown, if only a certain parameter, e.g. the maximum tensile stress has to be evaluated. Then the global response of the three-dimensional structure is compared with results of two-dimensional calculations assuming plane stress and plane strain, respectively. Subsequently the most interesting stress and strain distributions are discussed. The maximum value of stress concentration in front of the notch is given as a function of the applied stress. Additionally the state of deformation at fracture load is characterized by the plastic zone size, too. All three-dimensional results are compared with results of a plane strain model.