Modal energy propagation method in coupled systems of rigid and flexible structure

Abstract

Since the noise generated by mechanical structures affects the merchantability, it is important to predict it at the design stage. Statistical energy analysis (SEA), which solves the energy equilibrium equation between subsystems, is widely used to predict structural noise. However, due to the assumption that eigenmodes are treated statistically, SEA is limited to application in the high-frequency range with high mode density, so it is the challenge to develop vibration power flow analysis method for the low- and mid-frequency range. In this study, we propose a modal energy propagation analysis method to evaluate the vibration power flow between the eigenmodes of a subsystem. In this paper, the validity of the theory and the countermeasures to reduce the vibration by controlling the transmitted power between the eigenmodes are verified using a simple test apparatus. As a result, it was shown that the transmitted power between subsystems can be approximated by the summation of the transmitted powers of individual eigenmodes, confirming the validity of the calculation theory. In addition, it was confirmed that the mean square velocity of the subsystem can be reduced by identifying and controlling the transmitted power of individual eigenmodes using this method.

Keywords

• noise
• vibration
• modal analysis
• structure-borne sound
• component mode synthesis