Ductile fracture criterion and its calibration

A DCAMM seminar will be presented by

Professor Jeong Whan Yoon 1,2*

1Department of Mechanical Engineering, KAIST, Daejeon 305-701, Republic of Korea

    2Institute for Frontier Materials, Deakin University, Waurn Ponds, VIC 3216, Australia



Ductile fracture criterion is usually calibrated by shear, uniaxial tensile, plane strain tests. Stress-based fracture model is proposed in this study. It is observed that a nonlinear model with the mean stress shows a better correlation than the normal stress model. The shear point 
is very important to show the mean stress effect. However, it is often observed that triaxiality for shear specimen changes severely during shear fracture test and then the nonlinearity in triaxiality occurs. It is important to fabricate fracture specimens with minimum variation of triaxiality in order to characterize the ductile failure models accurately, where strain path is assumed to be linear. In this study, a “smiling” face shear specimen is optimized by minimizing the variation of stress triaxiality in the shear zone. In the optimization, Hill48 and Yld2000-2d (Barlat et al., 2003) criteria and Hill48 with non-associated flow rule are employed to model the anisotropic deformation of AA  6k21. The triaxiality plot for an optimized specimen based on Yld2000-2d is obtained experimentally. As an application, nonlinear strain path fracture including drawing, redrawing and expansion is presented. The proposed stress-based model with kinematic hardening shows excellent prediction of failure. Finally, simulation-based design of a long aluminum battery cell  (AA 3003) with D&I  is proposed for electric vehicle.

Danish pastry, coffee and tea will be served 15 minutes before the seminar starts.

All interested persons are invited.


Fri 14 Jun 19
14:00 - 15:00



Meeting room 121, building 404
DTU, Technical University of Denmark