ADVANCES IN MULTIAXIAL FATIGUE LIFE PREDICTION FOR COMPONENTS WITH STRESS-CONCENTRATIONS

Methodologies for predicting the multiaxial fatigue life of notched co mponents are reviewed and discussed. As background, a brief overview o f approaches for predicting the multiaxial fatigue life of smooth spec imens is presented. Representative test data generated prior to the mi d 1980s are summrized to demonstrate complexities involved in the mult iaxial fatigue behavior of notched specimens. During the past decade, research efforts on this topic have increased, with emphasis on the de velopment of new multiaxial fatigue damage parameters and approaches f or simulating notch elastic-plastic cyclic stress-strain behavior. Pro gress towards the application of simplified approaches, such as Neuber 's rule, to the prediction of notch stress-strain behavior for proport ional multiaxial loading is described. Other promising work for predic ting notch stress-strain behavior under nonproportional loading is sum marized. The newer approaches have considered blunt circumferential no tches or shoulder fillets and are based on surface stress-strain behav ior. Test data are shown which suggest that such approaches may not be adequate for other types of notches (e.g. splines) for which the effe ct of notch geometry and subsurface stress-strain distributions may be important. It is suggested that development of methodologies appropri ate for certain categories of notches may be the most fruitful approac h to take in future studies, rather than seeking a ''universal methodo logy''. (C) 1997 Elsevier Science Limited.