Papers by Keyword: Modal Density

Abstract: Statistical energy analysis (SEA) method is an adequate tool to solve complex problems to building acoustics. This research on the application in variety of the building materials as the subsystem of SEA model is performed. For the purpose to explore the relationship between the building element and its mode, these commonly used building materials are selected to determine this relationship. It is indicated that the properties of building material have obvious effect on the modal density and modal overlap of building members. As the consequence, a useful technique to account for a building member to be appropriate for a SEA (statistical energy analysis) subsystem is presented.

Abstract: A method to predict the modal density and radiation efficiency of orthogonally stiffened cylindrical shell is presented in this paper. The modal density is derived using energy method from the undamped natural frequencies of stiffened shell by treating the stiffeners as discrete elements. The band averaged radiation efficiency is estimated by categorizing the structural modes into acoustically fast and acoustically slow modes. The predicted parameters are compared with experimental results using laser vibrometer measurements. Phase-roll off has been observed in laser vibrometer measurements for which a correction procedure is applied. This prediction method can be easily extended to shells with stiffeners having different size, orientation etc.