Novel finite element for near real-time design decisions in multi-fastener composite bolted joints under various loading rates

In this paper, a highly efficient and novel user defined finite-element capable of modelling composite bolted joints at various loading rates was developed and validated against experimental data. The element was shown to be capable of producing high-fidelity simulations of joint behaviour up to and including catastrophic failure, with CPU times being orders of magnitude less than that required for full 3-D simulations, but with no loss in fidelity. Hence, this element makes possible for near real-time design decisions to be made for preliminary design and design for manufacture in multi-fastener composite bolted joints subjected to various loading rates. Using this element, this study finds that the load distribution in dynamically loaded multi-fastener joints is temporal and dependent on loading rate. The relative proportion of load carried by fasteners is found to vary due to the propagation of elastic stress waves in the joint. The magnitude of load imbalance between fasteners, an important design consideration to prevent premature joint failure, was observed to increase by up to 85% due to these dynamic loading effects.