Determining the Loss Factor by the Power Input Method (PIM), Part 1: Numerical Investigation

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. In this work, the power input method (PIM), which compares dissipated energy to the structure’s strain energy, was evaluated as a damping evaluation tool. Numerical simulations were used to analyze the lumped mass system (with custom software) and the plates (with commercial finite element software) and consequently to evaluate the assumptions required to apply the PIM. It was thus possible to find a way of minimizing the effect of the assumptions on the results, whose importance would be fundamental in the successive phase involving the experimental application of the method.