CONTINUUM DAMAGE MODEL OF LOW-CYCLE FATIGUE AND FATIGUE DAMAGE ANALYSIS OF WELDED JOINT

We know from experimental phenomena that the ductility of materials de creases with increasing numbers of cycles in the process of cycle fati gue loading, from which a new fatigue damage variable D-psi based on t he material ductility property is defined. Then a continuum damage mec hanics model for low-cycle fatigue is derived from the new damage vari able and is used to study the fatigue damage of welded joint. Damage e volution equations for the weld metal, heat-affected zone and base met al of 16MnR steel are obtained, respectively. The theoretical and expe rimental results show that the new damage variable D-psi has a definit e physical meaning and can be measured by a simple procedure and it ca n be related to the mechanical property of material directly. Copyrigh t (C) 1996 Elsevier Science Ltd