FAILURE ANALYSIS OF A CRACKED PLATE BASED ON ENDOCHRONIC PLASTIC THEORY COUPLED WITH DAMAGE

An anisotropic model of damage mechanics for ductile fracture incorporating the endochronic theory of plasticity is presented in order to take into account material deterioration during plastic deformation. An alternative form of endochronic (internal time) theory which is actually an elasto-plastic damage theory with isotropic-nonlinear kinematic hardening is developed for ease of numerical computation. Based on this new damage model, a finite element algorithm is formulated and when employed to characterize the fracture of thin aluminum plate containing a center crack. A new criterion termed as Y(R)-Criterion is proposed to define both the crack initiation angle and load. Experiments have been conducted to verify the validity of the proposed damage model and it is found that the theoretical crack initiation loads correspond closely with the measured values.