Analysis of micro/mesoscale sheet forming process with uniform size dependent material constitutive model

Based on accurate material models, finite element (FE) method becomes a powerful tool in conventional metal forming process design. However, conventional material models cannot describe the material behaviors in micro/mesoscale due to size/scale effects. As a result, most know-how obtained in traditional macroforming is not suitable for the microforming process. In the present study, a uniform size dependent constitutive model, describing the evaluation of the material behaviors from macroscale to microscale, is established by introducing the scale factor. It contains two different terms: size dependent term and size independent term. Moreover, SUS304 sheet specimens are prepared and uniaxial tension experiments are performed to validate the material model. Based on this uniform size dependent constitutive model, numerical simulation models of micro/mesosheet forming process are established to investigate the influence of the size effects. The results show that there is obvious difference in the punch force and Mises stress distribution between the results with consideration of size effects and that without size effects. Therefore, the size effects should be considered in micro/mesoforming process design. (C) 2009 Elsevier B.V. All rights reserved.