Monitoring of mechanical behaviors of composite shear fastener joint (2nd report, experimental study)

In a structural material of the aircraft, the proportion of composite materials keeps rising more and more because of their excellent properties on specific strength and rigidity. The part where a metallic material is connected to the composite material increases by such circumstances, and how a structural integrity in such a place is secured becomes an important problem. In previous paper, a principle of a method to monitor the mechanical behaviors using axial strain in fastener bolt was proposed. Here, we actually made the fastener with an optical fiber sensor embedded in the shank of a titanium bolt, and applied it to the composite/titanium mechanical shear joint specimens to prove the function of it through the tensile tests. The results are summarized as follows ; (1) proposed monitoring method is well available to monitor the load transfer mode around the fastener hole, (2) we can evaluate both the bearing loads acting to the shank of fastener bolt and the interfacial frictional loads between both materials by this method.