A study on measurement of envelope vibration intensity in plate

For reducing the vibration and noise of machine structures, it is important to clarify the excitation sources and transmission paths to each noise radiating wall. The measurement of vibration intensity that is expressed as a vector of flexural vibration energy flow transmitted through a structure seems to be useful for this purpose. The vibration intensity in a plate is usually referred to as a time-averaged intensity and is implicitly assumed to be steady. The envelope vibration intensity has intermediate properties between the instantaneous vibration intensity and the time-averaged vibration intensity. In this paper, the detection limits of envelope vibration intensity are discussed. For the measurement of the envelope vibration intensity, the three-channel method was employed. The vibration intensity vector was detected in a rectangular steel plate which was exited by impulsive forces on two points. As results of this experiment, it was clarified that was advantageous in the detection of transient vibration and its propagation in a structure.