Experimental Analysis of Impact-Damped Flexible Beams

Abstract

Statistical analysis of the phenomenon of impact damping is performed on 60 steady-state vibration tests of a flexible beam to relate the system's modal damping to system parameters. Compared with other measures of effectiveness of the impact damper, modal damping ratios are useful in predicting the response of continuous systems under arbitrary forcing functions. Contour plots show that the modal damping ratio is nonlinearly dependent on the damper's mass and gap. However, these are not the only parameters that control the effectiveness of the impact damper. Multiple nonlinear regression analysis of the data is used to test the dependence of the system's modal damping on a number of parameters. It is hypothesized that the system's parameters are the mass and gap of the impact damper, the excitation frequency, the peak of the frequency response function, and the modal amplitude at the location of the impact damper. Multiple nonlinear regression analysis shows the validity of the hypothesis and the ability of the derived formula to predict the modal damping ratio of the beam.