Influence of the fiber/matrix-interphase on the post-impact properties of glass/epoxy-laminates

In this paper the post-impact cyclic-dynamic properties and the compression-after-impact strength of glass/epoxy laminates with different fiber surface treatment are discussed. It was found that the fiber/matrix adhesion quality significantly affects the compression strength of glass/epoxy cross-ply laminates. The residual compression strength is a function of the adhesion quality at the fiber/matrix interface. The cyclic-dynamic tests have shown that the dynamic strength under tensional loading is qualitatively comparable to the results of the compression-after-impact test with respect to the examined materials. The dynamic stiffness of the plates is significantly reduced in the case of poor fiber/matrix adhesion compared to the specimen with good and medium adhesion. The damage growth in the impacted plates during the cyclic-dynamic testing is also a function of the adhesion quality. The stiffness decreases and the energy absorption increases much faster in the case of poor fiber/matrix adhesion which indicates the poor damage tolerance of these laminates. A linear relation was found between the accumulated dissipated energy and the specimen temperature rise.