Abstract
This paper derives a modal expansion of structural intensity for longitudinal vibration on beams. The expansion is expressed by the superposition of modal terms expressed by the product of weight coefficients and cross-modal functions. Cross-modal function is presented by the product of two modes with or without spatial derivatives. Numerical simulation is carried out in order to verify the modal expansion derived. The expansion is also applied to calculate the structural intensity on a beam system with the other beam as a branch. The comparison of one beam system and the branch system can introduce how we can utilize the modal expansion for structural intensity to design and develop structures.
