Abstract
A Finite element (FE) model considering mesoscopic material inhomogeneity due to a different flow stress for each crystal grain to predict free surface roughening is proposed. The effect of the standard deviation of the material inhomogeneity and grain size was investigated by the 2D FE model. In addition, to verify the model considering material inhomogeneity, the free surface roughening behavior is predicted under a bi-axial tension state using the 3D FE model. Furthermore, by comparison with experimental results, the validity of the FE model considering material inhomogeneity and its determination method is discussed. The standard deviation σsd of the material inhomogeneity parameter α in the model has a strong correlation with the rate of increase in the surface roughness, which increases with increasing grain size, is agreement with the conventional empirical equation. The surface roughness under bi-axial tension state is larger than that under uni-axial tension state. In addition, the experimental results are in good agreement with the simulation results. From these findings, we can verify the fundamental behavior and the validity of this model considering material inhomogeneity for the prediction of free surface roughening.
