Bayod J., Kamata M., Yamazaki T.

This paper describes an Experimental application of the Wave Intensity Analysis (EWIA) technique to simple plate systems. This research is focused on the simplification of the experiments to acquire the required transmission coefficients. EWIA uses coupling loss factors (CLF) and internal loss factors (ILF) obtained experimentally through the Power Injection Method, which is commonly applied in Experimental Statistical Energy Analysis (ESEA) for analysis of vibrations at high frequencies. SEA CLFs are angle-averaged and therefore these can represent just diffuse systems where energy can be considered same in every direction. On the other hand, WIA uses transmission coefficients to take into account the angular distribution of the energy exchanged between the subsystems. Therefore, experimental CLF data cannot be directly applied in EWIA and a relationship between CLFs and the angle-dependent transmission coefficients is required. This relationship is estimated by assuming a theoretical distribution of the energy at the boundaries. The technique is then applied to predict the energy levels of a simple plate system and the results are compared with directly measured energies, Analytical WIA and ESEA predictions. The results show that good correlation can be obtained with this method especially at high frequencies although it can be more sensitive than ESEA to common experimental errors in the mid and low frequencies. Complex systems very often include a number of non-diffuse subsystems that may reduce the accuracy of an ESEA model, the advantage of this EWIA application would be the possibility of estimating the energy levels in these types of systems without increasing the complexity of the method.