Monday  |  Salon 14  |  04:30 PM–04:50 PM

#16519–Comparative Study of Energy Dissipation Quantification Techniques using Measurements from Nonlinear Force Appropriation Testing

Energy dissipation is a critical quantity to identify to understand the dynamic performance of a mechanical design as the dissipation directly influences response amplification near resonance. In linear systems, dissipation is typically modeled with constant viscous damping that is proportional to the damping ratio and natural frequency for each mode and can be extracted directly from modal tests. For nonlinear systems there have been many proposed techniques for characterizing damping from experimental measurements, however researchers have yet to reach a consensus on which of these methods is optimal. This work investigates and compares several of these methods, utilizing response and input data typically available from a nonlinear force appropriation test. The study begins by conducting simulated experiments on single-degree-of-freedom models with different nonlinearities and extracting the nonlinear damping from the results using the different quantification techniques. These damping trends from each technique are compared against each other and validated with first order approximations of the nonlinear equations of motion. All techniques studied provided identical results for the systems analyzed if certain assumptions are satisfied. The final aspect of this work relaxes these assumptions systematically, and the corresponding changes in the damping trends are observed.

Benjamin Pacini   Sandia National Laboratories
Robert Kuether   Sandia National Laboratories