Evaluation of Thin Titanium Films—CFRP Fiber Metal Laminates for Composite Bolted Joints

Abstract

Fiber1metal laminates that consist of carbon fiber composites and thin titanium films are applied to bolted joint to obtain better bearing strength and reliability. Tensile tests for bolted joints in quasi1isotoropic CFRP laminates [45/0/145/90]2S and the hybrid laminates with five thin titanium films inserted to the CFRP plates are conducted. It has been found that load drop point in load – displacement curve corresponds to damage onset in the plate. As for the CFRP plate the micro1buckling of the carbon fiber in 0° layer (fiber kinking) occurs first and then matrix shear cracking in adjacent layers induced by the kinking follows. The propagation of the matrix shear cracking, on the other hand, is found to be prevented by the titanium films in the hybrid laminates. With the titanium films inserted to form sandwich with inner 0° layer lower damage level is presented compared to the plate with the outer 0° layers are sandwiched by the films since the shear matrix cracking propagates from inside toward surface.