STRUCTURAL ACOUSTIC RADIATION OPTIMIZATION OF A TRUNCATED CONICAL SHELL BASED ON FINITE ELEMENT METHOD

摘要

The complex thin-wall shell structures are widely used in aircrafts, they are difficult for parametric modeling or representing the geometric characteristics by general spline functions, therefore it is difficult for acoustic optimization. In this paper a structural acoustic radiation optimization model is established based on finite element method and mesh with structural-acoustic coupling. The control of acoustic radiation power for complex structure based on mode shapes is investigated to optimization of the structural-acoustic coupling characteristics. A truncated conical shell model with its conical angle, truncated length and internal volume as designed parameters is established, and the dynamic characteristics are obtained by analyzing its mode shapes by FEM, while the acoustic characteristics are obtained by Rayleigh integral, the mode shapes are integrated to define the shape optimization function. Finally, the geometric shape with the lowest structural acoustic radiation as the optimization goal is obtained. Meanwhile, the structural acoustic radiation optimization under harmonic excitation is carried out with the mean acoustic radiation power in the structural-acoustic coupling frequency range as the optimization goal. The numerical results of the truncated conical shell of aluminium alloy structure show that the method is effective for acoustic optimization.