Study On Acoustic-Structutal Design Sensitivity

The structural sound radiation and the acoustic-structural design sensitivity of cavum system in the sound field-structure coupling system are deeply studies in this essay. Today's study methods of structural sound radiation and the analyses of acoustic-structural design sensitivity throughout the world are analyzed. Comparisons are made by combining the adoptive range and limitation of each method. On the basis of parse theory of structural sound radiation in the sound field-structure coupling system, from the beginning of acoustics space fluctuating equation and shell theory, all kinds of finite conditions of sound field-structure are discussed, and the sound field-structure coupling system equation is got.Based on the finite element+finite element methods (FEM), the structural sound radiation and the acoustic-structural design sensitivity of cavum system are analyzed. The control equation of structural sound radiation by using FEM and the iterative equation of the acoustic-structural design sensitivity are derived. By using ANSYS finite software and the second development technology of it, calculation of structural sound radiation of cylindrical shell is made and the acoustic-structural design sensitivity of cylindrical shell is analyzed, and the correction of theoretical calculation is proved by combining with structure vibration mode test and with structural sound radiation measurement motivated by sine excitation. The structural sound radiation of passengers' cabin of Flight A340 under the cruise, excited by the engine, is theoretically predicted. The influence of seats and sound absorption materials on the structural sound radiation in the cabin was discussed. Using the thickness of cabin wall and the designed size of chamber sound space as structure variables instinctively, the acoustic-structural design sensitivity is analyzed.The analysis results show that sound absorption materials, location and number of seats and the parameter of shape of cabin and so forth have great influence on the acoustic response and sensitivity in the cabin of A340. The conclusions of this essay can provide theoretical gist and calculative basis for the structural sound radiation ofcavum system of cylindrical shell in sound field-structure coupling system, acoustic-structural design sensitivity analysis and the acoustic optimum design.