Forming limit diagrams: a micromechanical approach

A method for obtaining the forming limit diagram (FLD) from a micromechanic al approach is proposed. Periodic representative volume elements (RVEs) cha racteristic for the microstructure of a two-phase material containing parti cles are subjected to biaxial stretching with different strain paths. In th e course of straining, a groove forms and grows, finally leading to a stres s drop in the overall response. This deformation instability is obtained as a natural result of the strain field fluctuations caused by the inclusions in the two-phase material. For this approach, only the geometry of the mic rostructure and the material data of the constituents have to be known no a dditional assumptions about the deformation process or about a macroscopic inhomogeneity are necessary. The influence of the RVE representation on the possible deformation patterns is investigated. (C) 2000 Elsevier Science L td. All rights reserved.