Prediction of ductile failure using a phenomenological model calibrated from micromechanical simulations
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OriginalversjonProcedia Structural Engineering. 2016, 2 2543-2549. 10.1016/j.prostr.2016.06.318
Unit-cell models were in this study utilized to numerically determine the failure locus of a cast and homogenized AA6060 aluminum alloy. Simulations were conducted for moderate and high stress triaxiality ratios, and for various Lode parameters between generalized tension and generalized compression. We estimated the orientation of the localization band that minimizes the failure strain in the unit-cell models for all the imposed stress states. The energy based Cockcroft-Latham (CL) failure criterion was calibrated based on the numerically determined failure locus and used in finite element simulations that we evaluated against experimental tests. Test-specimen geometries included smooth tension tests, notched tension tests and plane strain tension tests. These were designed to cover a wide range of stress states. The points of failure in the experimental tests were predicted with reasonable accuracy by the numerical simulations. We see that the method used for numerically determining the failure locus can be improved by refining the micromechanical simulations. Better agreement between the simulations and the experiments can also be obtained, for instance by employing a different macroscopic failure criterion than the CL criterion.