2010 年 76 巻 772 号 p. 3316-3322
In order to utilize the vibration intensity (VI or structure intensity), it is necessary to clarify characteristics and usability of VI under conditions close to practical situations. The superposition of standing wave and traveling wave often occurs in actual structures. In the vibration field with a standing wave and a traveling wave, it has been reported that a curved energy flow is detected by VI unlike the case without the standing wave. It has not been validated whether the energy flow detected by VI in the case with standing wave is equal to the real energy flow. VI detects the transmission component of vibration energy. However, the standing wave is non transmission component. The influence of the standing wave on VI is still unclear. In this study, a thin plate model with a standing wave and a traveling wave was employed, and we investigated the influence of superposition of these waves on VI using finite element method (FEM) analysis. The usability of VI under this condition was evaluated. Main findings are as follows: The extra terms appear in the VI formula when the superposition of multiple waves occurs. The difference between VI with standing wave and that without it is generated by these terms. VI approximately detects real energy flows when amplitude ratio of traveling wave to standing wave is greater than five.