Mechanical behaviour of brittle matrix composites: a homogenization approach

A numerical model is developed with the aim of describing the macroscopic mechanical response of unidirectional brittle matrix _ber!reinforced composites subjected to stresses acting in any plane transverse to the _bers[ Finite element analyses of a representative unit cell are performed\ with suitable boundary conditions ensuring continuity of the displacement _eld across adjacent cells and periodicity of the strain _eld over the cell[ A strain softening constitutive law is adopted for the matrix in tension to allow\ for instance\ for brittleness induced by possible defects in a polymeric matrix[ The perfectly plastic case is also considered for sake of comparison[ Results established for ductile composites are found to be inappropriate for brittle matrix composites] numerical analyses show that composites with softening matrix have transverse strength properties much poorer than perfectly plastic composites with matrix of equal strength\ and even than the unreinforced matrix[ An induced transverse anisotropy in the post!peak regime is also observed[ A discussion on the proposed approach concludes the note