NUMERICAL-ANALYSIS OF COMPOSITE SYSTEMS BY USING INTERPHASE INTERFACEMODELS/

The paper considers two classes of approaches for the numerical analys is of composite systems: the first one discretizes the assumed interph ase (between matrix and fibre) as volumic elements and uses material m odels that degenerate from Continuum Damage Mechanics. The second one introduces interface elements that relate non linearly the normal and tangential tractions to the corresponding displacement discontinuities , incorporating a progressive decohesion, following the lines of Needl eman (1987) and Tvergaard (1990). The respective capabilities of these two approaches are discussed on the basis of some numerical results o btained for a unidirectional metal matrix composite system. When the m odels are consistently adjusted they are able to reproduce the same ki nd of results. The advantages of the second class of method is underli ned and two new versions of interface models are proposed that guarant ee the continuity and the monotonicity of the shear stiffness between the progressive decohesion phase and the subsequent contact/friction l aw that plays role under compressive shear after complete separation.