Abstract
This paper describes the classification of the behavior of instantaneous longitudinal structural intensity on beam. Structural intensity is defined as the instantaneous rate of energy transfer per unit area of beam and is calculated by the product of stress and velocity. Then the stress and longitudinal velocity and structural intensity on a simple beam are calculated by using numerical simulation based on finite element method. We consider the two conditions in transient and in the steady state are considered to discuss the behaviors of the instantaneous structural intensity. As a result, the behaviors can be classified into three cases under the resonant with small damping, under the non-resonant with small damping, and under the large damping. In the transient condition there is no difference between the three cases. On the other hand in steady state condition, the phase difference in each case between the stress and the longitudinal velocity are different and then the structural intensity behaviors are different.
