The effect of changing of heterogeneity with strain on the forming limit diagram

Abstract

The heterogeneity coefficient of deformed sheet metal described by surface roughness was introduced into Jalinier theory of computation of forming limit diagrams. The surface roughness is changed during sheet deformation, and in the similar manner the heterogeneity coefficient is altered. Taking into account the changing of heterogeneity coefficient during forming of sheet the effect of grain size and strain paths on the limit strain of steel and aluminium was analysed. © 1992.