Study on error of vibration intensity measurement in a flat plate with multiple energy flows entering from outside

Abstract

Vibration Intensity (VI) method can show flows of vibration energy in surface of mechanical structures as a vector quantity and is one of the techniques to identify vibration source and vibration transmission path. Some previous studies have showed that if there are multiple vibration sources in the analyzed plate, VI causes error due to superposition of multiple waves. In actual structures, however, the vibration source often exists outside of the analyzed plate which is surrounded by the boundary with reflection, such as curved parts and staged parts. The VI error has not been investigated in such cases close to actual structures. The purpose of this research is to investigate the influence of superposition of multiple waves which come across the stepped boundary into a flat plate on VI by using finite element method analysis. This model also simulates the case with the superposition of progressive wave entering from the outside of the plate and reflected wave caused at a boundary of the plate. The results of calculation showed that the superposition of waves causes a difference between VI and real vibration energy flow, depending on frequency and plate size.