Application Of Emmc Model To Fracture Of Metal Sheets

The fracture properties of TRIP780 and magnesium AZ31B-H24 alloy sheets were investigated in this paper. Mechanical experiments were performed for TRIP780 under uniaxial tension, notch tension, punch test, and plane strain tension. Mechanical experiments were performed for magnesium AZ31B-H24 sheets under different loading conditions, including monotonic uniaxial tension, notch tension, in-plane uniaxial compression, wide compression (or biaxial compression), plane strain compression, through-thickness compression, in-plane shear, punch test, and uniaxial compressiontension reverse loading. The stress invariants based Modified-Mohr-Coulumb (MMC) fracture model was transferred into an all-strain based MMC (eMMC) model under the plane stress condition, predicting the fracture strain in the space of strain ratio or Φ angle, instead of stress triaxiality and Lode angle parameter. The strain ratio or Φ angle could be directly measured by digital image correlation (DIC), while the latter required finite element analysis to be determined. This method made it possible to study fracture of materials while bypassing plasticity. Using the fracture strain measured by DIC, fracture locus was calibrated by the all-strain based MMC model. The fracture strain was extended by using a linear transformation operating to the plastic strain tensor to incorporate the anisotropic fracture behavior. Good prediction capability has been demonstrated for these two materials