文摘
An original experimental method is proposed to characterize the influence of matrix damage on the compressive strength of laminated composites in the fiber direction using tubes. These composite tubes have a dumbbell-shaped geometry so that rupture occurs in the specimen center without stress concentration. They can be constituted of unidirectional or woven plies aligned with the axial direction. First, a torsional cyclic load is applied in order to damage the matrix. This damage is measured at the tube scale via the reduction in shear modulus. Second, a compressive load is applied up to failure for various damage levels.The method is applied to a woven carbon/epoxy material. Results show that the matrix damage affects significantly the compressive strength in the fiber direction. It is yet observed that longitudinal stiffness is not modified by damage. Finally, a simple model is proposed to describe this decrease of strength vs. matrix damage.