Performance review of various uncoupled fracture criteria for TRIP steel sheet

Abstract

The exact numerical description of ductile fracture for advanced high strength steel (AHSS) sheets, particularly for different deformation modes, is an ongoing issue for the sheet metal research community at large. Although, in the last few decades, several research groups have proposed different fracture criteria, there is no consensus on suitability of one particular criterion especially for AHSS sheets. Hence, in the present work, the performance of six important fracture criteria was assessed for TRIP1180 sheet deformed under different loading conditions. Mechanical tests that induce different loading conditions - uniaxial tension, bulge, shear, hole-expansion, plane strain and 3-point bending tests, were conducted. A finite element study was performed using a commercial explicit finite element solver integrated with an appropriate material subroutine. The constitutive equations and material parameters were taken from a previous work carried out on the same TRIP1180 sheet. Finally, six uncoupled fracture criteria were applied to describe the fracture in numerical simulations. The study showed that traditional uncoupled fracture criteria describe the fracture reasonably well. Results also revealed that a high number of fracture coefficients are no guarantee for improved fracture prediction under different loading conditions.