Measurements of tangential stiffness and damping of mechanical joints: Direct versus indirect contact resonance methods

Mechanical joints are integral to modern structures and provide coupling forces, moments and damping between connected substructures. A widely used approach to modeling such structures with multiple joints is to use physical joint parameters of tangential stiffness and damping, which are difficult to obtain. In this paper, two experimental methods, referred to as direct fretting loop and indirect contact resonance methods are utilized to measure the tangential stiffness and damping of aluminum joints. The stiffness values obtained from both methods are in good agreement with each other and with the literature. Comparison and limitations of the two methods are presented.