A damage mechanics based approach for fracture of metallic components

In the present paper, the distribution and evolution of damage field in single edge cracked three-point-bending and centre cracked tensile specimens are analysed. The dissipation of the specialised ductility is taken as the damage variable in the damage model based on irreversible thermodynamic (IT). The stretched zone size (SZW) is proposed as the characteristic scale in this study. Steel StE 690 was used to perform the tests at Aachen Technical University. By changing the relative crack length of the specimens, it shows that though the critical J integral for physical crack initiation varies from one specimen to another significantly, the corresponding critical values of the specialised parameter based on the damage theory accumulates close to one constant. It indicates that the prediction from the damage theory is independence of the stress states and geometry of specimen.