Necking and softening as a consequence of latent continuum damage

Necking and softening in ductile polycrystalline metals are modeled as cons equences of continuum damage (CD) that consists in braking through of barri ers resisting plastic deformation. Our model describes these materials as t wo-phase continua consisting of microdomains with easy glide and barriers w ith decreasing continuity in the course of deformation. Macroscopic homogen eity and increase of macroscopic stress with increasing deformation are con ditioned by sufficient continuity of these barriers. Our model describes th e whole course of engineering stress-strain diagrams up to rupture and the differences in the diagrams for test specimens of different length. The mod el is compared to experimental data measured on two materials - sorbitic st eel and an AlMg3 alloy. (C) 2001 Editions scientifiques et medicales Elsevi er SAS.