DAPHNIS - A NEW MODEL FOR THE DESCRIPTION OF POST-LOCALIZATION BEHAVIOR - APPLICATION TO SANDS

This paper addresses developments on a constitutive model able to desc ribe the post-localized behaviour of structures composed by geomateria ls. The behaviour of the shear band is defined by means of a specific non-linear constitutive equation in the framework of large strain. Con cept of 'consistency' of this model with the CLoE model from which it is derived at the onset of localization is discussed. During the post- localization regime this model evolves in a specific way by introducin g the concept of critical void ratio. After some recalls about the CLo E framework and about a Rice bifurcation analysis involving CLoE model s, the basic concepts of the Daphnis model are introduced. The last pa rt of this paper is devoted to numerical results on an initially homog eneous frictionless biaxial test. The behaviour of the sample is model led by means of a plane Mohr Coulomb model defined in the CLoE framewo rk and its associated Daphnis model is used to characterize the specif ic behaviour of the shear band in the post-localization regime. (C) 19 98 John Wiley & Sons, Ltd.