Estimation of Input Power to Structure in Machine Operation Using Energy Analysis

Abstract

This paper presents a method for identifying the input power to a structure in machine operation using energy analysis models such as the Statistical Energy Analysis (SEA) and Energy Distribution (ED) models. The basis of this method is that the vibrational energies of the respective subsystems during operation can be measured with a velocimeter or accelerometer at the same measurement locations as in the constructed SEA and ED models. Generally, the identification of the input force in machine operation is accomplished by Transfer Path Analysis (TPA). With TPA, however, identifying the input forces is difficult when their locations are not clear. On the other hand, energy analysis models are excellent in cases of unclear input force locations. As for the ED model, the model accuracy is high in the low-frequency range, although model construction is more demanding than for SEA. In this study, the accuracy of input power identification using SEA and ED models is verified through numerical analysis using the finite element method and experimental tests on a simple structure consisting of three subsystems connected in series. As a result, if the location and the number of excitation and response points can be distributed appropriately within the subsystem, the identification of input power is effective and quantitative.