Determining the Loss Factor by the Power Input Method (PIM), Part 2: Experimental Investigation with Impact Hammer Excitation

Abstract

Damping must be accurately determined in the design and/or optimization of vehicle and aircraft trim. Yet, owing to the complexity of the dynamic interaction among the components in trimmed panel systems, until now it has been difficult to obtain reliable damping estimates. The power input method (PIM) was numerically investigated in Part 1 of this work. The results regarding how to reduce the effects of the assumptions required to apply the method were put into practice through the experimental activity with impact hammer excitation described in this work. The experimental testing was conducted on flat and bent steel plates of various sizes trimmed with damping material. A method, called the “numerical updating technique” (NUT), was developed to reduce the number of measuring points and the effects of the discretization on the kinetic energy estimation. Comparison of the numerical and experimental results has validated the reliability and suitability of the proposed method.