Abstract
Bolted joints are widely used to assemble plate structures and a proportion of the system damping is provided by the joints. Although the damping characteristics in a bolted plate structure are different from mode to mode, the difference of damping mechanism between the modes is not clear. In this paper, we investigate the damping mechanism for the modes of the 1st and higher of bolted plates which partially overlap. We use finite element analysis (FEA) to obtain the mode shapes form a linear FE model and the contact information such as contact pressure, contact area and sliding distance at the contact surface from a nonlinear FE model. First, we evaluate the difference in the damping ratio of the modes based on the mode shapes. Second, we evaluate the damping mechanism based on the frictional dissipation energy estimated from the contact information. The validity of the estimation procedure is shown by comparing the estimated and measured modal damping ratios form a test structure consisting of three plates bolted.
