An estimation of vibration intensity from the measured vibration locus at one point

Vibration intensity is a useful quantity for indentifying vibration sources and propagation paths, which shows the magnitude and direction of vibration energy flow, and it has been calculated using multi-point vibration data through finite-difference (FD) method in previous studies. This report presents a method to estimate the structural intensity from the vibration at one point: the in-plane and out-of-plane vibration displacements. We apply this method to one-dimensional beam and two-dimensional plate, and compare the error with the conventional FD method. The proposed method has small error for estimating transmission power especially under weak standing wave condition in a beam. The authors also propose a simple device to display the magnitude and direction of transmitted power, which is based on the nature of vibration locus in flexural vibration. A small plate placed at the top of the device rotates in accordance with the transmitted power level.