STRAIN AND STRAIN-RATE SOFTENING INSTABILITIES - LENGTH SCALES AND SPATIAL COUPLINGS

Propagating plastic instabilities can be of strain rate softening type (Portevin-Le Chatelier effect) or of strain softening type (Luders and Luders-like phenomena). The constitutive modelling of these instabilities is discussed with particular reference to spatial aspects. The spatial couplings deriving from various possible mechanisms for slip propagation are reviewed and the need for new critical experimental checks is emphasized.