A FINITE-ELEMENT ANALYSIS OF THE RESIDUAL-STRESS DISTRIBUTION IN THE VICINITY OF A FATIGUE FRACTURED SURFACE

An analytical study by the elastic-plastic finite element method was m ade of the residual stress and equivalent plastic strain distributions near the fatigue crack surface. Emphasis was on finding the correlati on between the residual stress on the fracture surface and the applied stress intensity factor range Delta K. Special attention was given to the effects of applied stress ratio and the work-hardening rate. A ch aracteristic behavior was found: the residual stress on the fracture s urface increases with the increase of Delta K, reaches a maximum at a certain value of Delta K, and then decreases. The decrease of the resi dual stress on the crack surface was correlated with the growth of an instability into the distributions of residual stresses and equivalent plastic strain under the fracture surface. It was also found that bot h the residual stress and equivalent plastic strain distributions unde r the fracture surface were useful for the estimation of the monotonic plastic zone size or K-max and the cyclic plastic zone size or Delta K. (C) 1998 Elsevier Science Ltd. All rights reserved.