Experimental analysis of dynamic characteristics in bolted joint interfaces of thin plates

In this paper, the authors explore the dynamics characteristics of bolted joint interfaces in thin plates, focusing on the uncertainty in stiffness and damping due to variations in contact interfaces. The research primarily investigates joint stiffness and damping caused by energy loss in bolted connections, particularly under conditions of varying bolt torque. A unique experimental setup employing nonlinear modal testing is used to analyse the complex behaviour of bolted joints. This setup includes phase-resonant testing to accurately track the backbone curves of nonlinear frequency responses, which is essential for understanding the mechanicalproperties of bolted joints. The experimental findings focus on the relationship between bolt torque loosening and the resultant stiffness and damping effects, offering insights into the complex interplay between structural integrity and damping efficiency. This study contributes to the modelling of damping in bolted joints, addressing the inherent uncertainties and nonlinearities in such systems. The results have significant implications for improving the prediction and optimisation of damping in assembled structures with bolted joints, with potential applications in various engineering applications.