Reliability of experimentally determined damping values

In order to increase the reliability and precision of numerical models for vibro-acoustic problems, it is often still necessary to extract and validate input parameters by performing experiments. Among the frequently needed input parameters for finite element models, damping is one of the most difficult ones to acquire. One of the reasons for those difficulties is that the boundary conditions commonly used for numerical models, e.g. free-free support or ideally clamped are not precisely feasible in an experimental setup but are mere approximations. Since the utilized type of support can affect the obtained experimental damping values, it can be necessary to pay close attention to the design of the experimental setup. The focus of this study is set on the influence of different types of support on experimentally obtained damping values. The structural dynamical response of the used test specimen with different types of support on an impulse excitation is measured by a laser scanning vibrometer. During post-processing, the damping values are derived from the measurements and are further analysed.