On the Ohno-Wang kinematic hardening rules for multiaxial ratcheting modeling of medium carbon steel

This paper evaluates the performance of four Ohno-Wang type constitutive models in predicting ratcheting responses of medium carbon steel S45C for a set of axial/torsional loading paths. Suggestions are also made for further modification. The four models are the Ohno-Wang model, the McDowell model, the Jiang-Sehitoglu model and the AbdelKarim-Ohno model. It is shown that the Ohno-Wang model and the McDowell model overestimate the multiaxial ratcheting. Whereas, the Jiang-Sehitoglu model yields good predictions for most loading conditions used in this study with an appropriate modification of the dynamic recovery term. The AbdelKarim-Ohno model gives acceptable predictions for all considered multiaxial conditions when used with an evolution function for mu(i), but gives poor predictions of uniaxial ratcheting if the parameter mu(i) is determined from a multiaxial ratcheting response. A new modified Ohno-Wang hardening rule is proposed for better adaptability under diverse situations by multiplying a factor to the dynamic recovery term, which is dependent on noncoaxiality of the plastic strain rate and back stress. This new model predicts ratcheting strain reasonably well for the test cases. (C) 2004 Elsevier Ltd. All rights reserved.