Numerical Simulation of Fatigue Crack Propagation in Round Bar Using S-FEM and Experimental Verification

In this paper, a methodology for a three-dimensional simulation of fatigue crack growth behavior in a round bar is presented. This method is based on linear elastic fracture mechanics and S-version FEM (S-FEM) is employed for numerical analysis. Plasticity induced crack closure effect is considered by integrating a crack opening model into simulation method. This crack opening model is obtained from a result of a cyclic elastic-plastic finite element analysis. The accuracy of the solution for stress intensity factor (SIF) is checked by comparing with the available solutions in literature. For verification, experiments are conducted on round bars with single cracks and two cracks. A simulation of single crack propagation is conducted and the crack shape change prediction is compared with the experimental result. Two cracks problem is qualitatively investigated by experiments. In simulation, the shape change and SIF are shown. Results give acceptable predictions comparing to Experimental results. It is notable that the behavior of two cracks on the different plane can be easily simulated. The interaction of two cracks is discussed.