Forming simulations based on parameters obtained in microstructural cold rolling simulations in comparison to conventional forming simulations
This work demonstrates a first approach of using virtually obtained material properties as input for forming simulations. The necessary parameters to apply a Barlat-Lian89 yield surface are computed in the so called “Virtual Lab”, which performs FE-simulations on previously cold rolled volume elements to predict the distribution of grains. The resultant stress-strain-curves serve as input parameter for a deep drawing simulation. For reference, an ordinary material data file determined by real uniaxial tension tests is compared to the virtual based material data file. Further, the results of both simulations are exhibited to allow a first evaluation of the deviation from each other. In particular, the Lankford Parameters in 0° and 90° with respect to the rolling direction are predicted by the Virtual Lab quite well. Only the 45° value requires improvement for future analysis of material properties. Likewise, the extrapolation of the hardening curve shows a strong deviation at larger deformation. The equivalent plastic strain as well as the thickness reduction is less affected by this problem. However, the calculation of the equivalent stress is influenced strongly by the deviating hardening curves at larger strains. This expresses itself in an overestimation of the stress in the simulation as based on the virtually obtained properties.
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Forming simulations based on parameters obtained in microstructural cold rolling simulations in comparison to conventional forming simulations
This work demonstrates a first approach of using virtually obtained material properties as input for forming simulations. The necessary parameters to apply a Barlat-Lian89 yield surface are computed in the so called “Virtual Lab”, which performs FE-simulations on previously cold rolled volume elements to predict the distribution of grains. The resultant stress-strain-curves serve as input parameter for a deep drawing simulation. For reference, an ordinary material data file determined by real uniaxial tension tests is compared to the virtual based material data file. Further, the results of both simulations are exhibited to allow a first evaluation of the deviation from each other. In particular, the Lankford Parameters in 0° and 90° with respect to the rolling direction are predicted by the Virtual Lab quite well. Only the 45° value requires improvement for future analysis of material properties. Likewise, the extrapolation of the hardening curve shows a strong deviation at larger deformation. The equivalent plastic strain as well as the thickness reduction is less affected by this problem. However, the calculation of the equivalent stress is influenced strongly by the deviating hardening curves at larger strains. This expresses itself in an overestimation of the stress in the simulation as based on the virtually obtained properties.