Fatigue Life Assessment of Steel Samples undergoing various IrregularMultiaxial Loading Spectra through Energy-based Damage Models

Fatigue damage of materials undergoing multiaxial irregular loading spectra was aluated on the basis of energy descriptions of Macha and Varvani. Macha evaluated the life of samples from calculation of the equivalent strain energy density histories on the critical plane over counted cycles. Based on the equivalent relative strain method of the Wang-Brown, multiaxial peak-valley events were counted. Varvani assessed fatigue damage of componentsinvolving the normal and shear energy ranges acting on the critical plane where the largest stress and strain Mohr’s circles during peak-valley events are achieved. The predicted lives based on damage descriptions were furtherdiscussed and compared with those data of experimentally reported in literature.

Keywords:

Multiaxial fatigue , irregular loading , cycle counting , fatigue damage , life prediction