MECHANICAL CHARACTERIZATION AND MODELING OF NONLINEAR DEFORMATION AND FRACTURE OF A FIBER REINFORCED METAL MATRIX COMPOSITE

The non-linear anisotropic mechanical behavior of an aluminum alloy metal matrix composite reinforced with continuous alumina fibers has been determined experimentally. The mechanical behavior of the composite has been modeled by assuming that the composite has a periodical microstructure. The resulting unit cell problem has been solved with the finite element method. Excellent agreement was found between theoretically predicted and measured stress-strain responses for various tensile and shear loadings. The stress-strain responses for transverse and in-plane shear were found to be identical and this will provide a simplification of the constitutive equations for the composite. The composite has a very low ductility in transverse tension and a limited ductility in transverse shear that has been correlated to high hydrostatic stresses that develop in the matrix. The shape of the initial yield surface has been calculated and good agreement was found between the calculated shape and the experimentally determined shape.