Measurement of Envelope Vibration Intensity in Plate.

The vibration intensity transmitted through a plate is usually referred to as a time-averaged intensity and is implicitly assumed to be steady. In this paper, the envelope vibration intensity was proposed, which has intermediate properties between the instantaneous vibration intensity and the time-averaged vibration intensity. For this purpose, the three-channel method, which can yield changing magnitude and direction of the intensity vector through a single measurement, was introduced. The experiments were carried out on a rectangular steel plate to investigate the effectiveness of the envelope vibration intensity, detecting the transient feature of the intensity vector. Then, detection limits of the envelope vibration intensity were also discussed. As a result of this experiment, it was clarified that the envelope intensity was advantageous in the detection of transient vibration and its propagation in a structure.