Experimental and numerical investigation on the impact response of a riveted structure subjected to bird strike

The present study deals with the impact response of a certain type of riveted structure, comprised of three Ti6Al4V plates jointed by ten rivets, under bird strike. At first, bird impact tests were conducted on the riveted structure at different impact velocities. Results indicated that failure mode of the riveted structure manifested as fracture of all the rivets on one side of the structure. And the threshold impact velocity for the current 50-g cylindrical gelatin bird projectile to cause failure of the riveted structure fell within the range of 115 m/s to 127 m/s. In order to realize the utilization of simplified connectors in bird strike simulations in place of actual rivets, a novel connector model incorporating the coupling effects of loading state and loading rate was introduced. Subsequently, based on the force-displacement curves of the currently employed riveted joint under five distinct loading states and three varying loading speeds (5 × 10⁻⁵ m/s, 12 m/s and 17 m/s) reported in preceding study, the capability of this model in characterizing the nonlinear and failure behavior of the riveted joint under complex loading conditions was verified by implementing it into finite element codes. At last, bird impact simulations for the riveted structure were carried out using a simplified model, where the connected plates and rivets were modeled with shell elements and simplified connectors, respectively. Remarkable consistency was observed between the simulations and the experimental results, notably in regards to the threshold impact velocity, high-speed photographs, failure mode and strain responses. Consequently, it is concluded that the present simplification approach for simulating bird strikes on structures incorporating rivets demonstrates exceptional reliability.