Improving the mechanical performance of unidirectional CFRP by metal-hybridization

Abstract

In CFRP primary structures the fraction of fibers aligned in load direction is limited due to the material’s notch and impact sensitivity. As a result, stiffness and strength per unit weight of the laminate on a given direction are lower than the corresponding values for a unidirectional composite. The present investigations show that the on-axis residual-strength-after-impact of unidirectional laminates can be increased significantly by interleaving thin steel foils and highly orthotropic laminates become applicable. Grit-blasting, as a common pre-treatment process for stainless steel surfaces, is not feasible for thin foils due to the increased risk of damaging the metallic substrate. Therefore, different pickling processes are investigated as a non-mechanical alternative pre-treatment. Thus, superior adhesion properties are achieved compared to mechanical pre-treatments.