Effect of pitch distance, row spacing, end distance and bolt diameter on multi-fastened composite joints

Two-dimensional finite element modelling has been used to determine the contact stress and load distribution in a multi-fastened composite laminate plate forming the inner lap of a double-lap joint configuration subjected to tensile loading. The effect of both elastic and rigid outer laps was investigated. The results obtained for the former showed good agreement with previously published work. For a double row multi-fastened joint with rigid outer laps the effect of pitch distance, row spacing, end distance and pin diameter on the percentage of load transferred via the inboard and outboard rows was investigated. Friction at the interface was shown to exert a considerable effect on the local contact stress distribution around each hole. These results provide guidelines for the design of double row multi-fastened composite lap joints based on the optimum load transferred through the fasteners.