Kozien M.

The useful method of analysis of power flow paths for vibrating systems of surface structural elements are based on the sound structural intensity vector distribution. It can be done theoretically (numerically) or experimentally. The theoretical methods are based on the analysis of vibration of the structure by finite element method and determination of the structural intensity vector. The well-known methods of experimental determination of the considered vector are the source of the transducer mass effect. This effect can be minimized by application of the only strain signals type measurements and using relatively low mass transducers as classical strain gauges or PVDF elements. Application to the measurements a video signal varying in time, gives a possibility to determine the structural intensity vector with no mass effect. Analysis of the image registered by the video camera makes possible to analyse the displacement of chosen points on the external surfaces of the element and then to determine the suitable strains components. By application of the stain measurement methods the determination of power flow in two perpendicular directions is possible. Theoretical basis of the method and some experimental remarks are discussed in the paper.