An analytical model for strength prediction in multi-bolt composite joints at various loading rates

This paper presents an enhanced analytical model to determine the complete load displacement curve of single- and multi-fastener composite joints. It is an extension of a previous spring-based method, which included the effects of bolt pre-load and clearance, but not local bearing damage. The model has advanced beyond the state-of-the-art as loading rate effects, in addition to bearing damage, are accounted for through a novel conic damage approximation function. Using the developed model, an accurate prediction of the load displacement response of single- and multi-fastener joints to complete failure can be obtained in a matter of seconds. The method is validated against experimental data and excellent correlation was observed. Further studies carried out using the model suggest that slight variations in the energy absorption characteristics at each fastener hole in a multi-fastener joint can significantly alter the bolt-load distribution in the joint.