A Study on Comparison between Input Powers and Contribution Rates from Statistical Energy Analysis and Transfer Path Analysis on a Mechanical Structure

Abstract

This paper presents a method for comparing the input powers and contribution rates from a power source to a structure in machine operation determined by statistical energy analysis (SEA) and transfer path analysis (TPA). Identifying external forces and contribution rates from input power sources during machine operation is important for analyzing machine and equipment, and dynamic designs. SEA is used for systems with many resonant modes, and predicted results are based on spatial averages. In contrast, TPA is based on estimation of a frequency response function between an excitation point and a response point. In this study, a method is proposed for comparing SEA evaluated by the power injection method and TPA evaluated by the matrix inversion method. The proposed method is validated through numerical analyses, using a finite element method of a simple structure consisting of two flat plates connected in an L-shaped configuration and a partial car model consisting of four subsystems. As a result, the SEA input power is spatial averaged over each subsystem quantitatively agrees with the TPA input power expressed as the product of the force and velocity at the excitation point. Contribution rates from a power source, the SEA and TPA results are qualitatively similar without having to consider the phase.