Application of the Gurson Model to Ductile Tearing Resistance

Abstract

Compared with conventional fracture mechanics concepts, constitutive equations which account for local damage of the material have the advantage that the corresponding material parameters for ductile fracture can be transferred between different specimen geometries. They will hence be able to describe the physical effect of constraint on the tearing resistance in a natural way. The paper shows the capabilities of the GURSON model in predicting JR-curves for different specimen geometries under static and dynamic loading with one set of material parameters. It is shown how these parameters can be determined from the numerical simulation of simple tensile tests. Problems and open questions are discussed and perspectives for future applications are given.

Two mechanisms of ductile fracture: void by void growth versus multiple void interaction

“…6a and b, revealing the tendency for all the voids near the tip to experience growth. One feature of the growth of the voids that can be seen in both cases is their tendency to become oblate, as is expected from basic results for growth of voids at high stress triaxiality (Budiansky et al, 1982), and as noted also by Aravas and McMeeking (1985).…”

“…An alternative possibility for conducting the present investigation would have been to make use of the highly effective computational models of ductile fracture developed over the past decade which employ void-containing elements based on constitutive models such as that of Gurson (1977). There is now an extensive literature on these models represented by papers of Needleman and Tvergaard (1987), Rousselier (1987), Brocks et al (1995) and Gao et al (1998). While these models do not resolve the growth of individual voids with the accuracy of the present approach, they should be capable of elucidating the two mechanisms referred to above.…”

Fracture and damage mechanics modelling of thin-walled structures – An overview

“…In fact, numerous successful applications of damage models of the "porous metal plasticity" family exist via the implementation in the framework of finite elements [94][95][96][97]. The models were used for the assessment of thick-walled geometries, where a high constraint causes a high triaxiality and thus void growth has a significant effect on the stress carrying capacity of a material point.…”

Micromechanics-based model for trends in toughness of ductile metals

“…This approach is computationally intensive and is able to account for only a few voids ahead of the crack tip. ț An alternative approach, which has been pursued mainly by groups in France, Germany, the UK and the US [10][11][12][13][14][15][16][17][18][19][20][21], employs a constitutive model, such as the Gurson model, that accounts for the damaging effect of voids. The constitutive model is implemented in a finite element code to simulate the initiation and growth of the crack.…”