Abstract：Based on the critical plane approach, the drawbacks of the WB model are analyzed. It is discovered that, the normal strain excursion between adjacent turning points of the maximum of shear strain cannot reflect the effects of the additional cyclic hardening well; in the meantime, the empirical constant contained in the WB model is a life-correlated parameter which cannot be completely determined by the tensional and torsional fatigue limit. In addition, a new multiaxial fatigue damage parameter is developed to overcome the drawbacks of the WB model. The new damage parameter integrates the strain parameter with the energy parameter which the normalized stress range is used, and moreover, a new stress-correlated factor is introduced to account for the additional cyclic hardening which were caused by the non-proportional loading. It is convenient for engineering application because of no empirical constants in this parameter.
2010, Vol. 31 
