壳间连接形式对双层壳声辐射性能的影响

EFFECT OF CONNECTION TYPE BETWEEN INNER AND OUTER SHELLS ON CHARACTERISTICS OF SOUND RADIATION FROM FINITE DOUBLE CYLINDRICAL SHELL

研究流场中受径向点激励的有限长双层圆柱壳壳间用实肋板连接或用托板连接对其振动和声辐射性能的影响。壳体的振动用Flügge壳体方程描述,将加强构件等价为对内外壳体的支持力,实肋板作用可以等价为周向、轴向和径向三个方向的力和轴向弯矩作用到壳体上。托板近似简化为拉压杆件进行计算,并推导了托板的动反力公式,然后将其引入壳体振动方程,最后求解双壳体声-流体-结构耦合方程,计算结果用辐射声功率、表面振动均方速度级和辐射效率的形式表示。在数值分析部分,讨论了壳间连接型式变化对双层圆柱壳的声辐射性能的影响,分析了托板和实肋板的差别。得出结论:壳间连接越紧密,对应的双层加筋圆柱壳的辐射声功率越高。

The effects of connection types, namely the annular plates connection and the splints linking between inner and outer shells on vibration and sound radiation from a finite double cylindrical shell driven by a point force on the shell surface in the radial direction are studied. The Flugge equation of thin shell is applied to describe shell motion. The effects of stiffeners are treated as reverse forces and moments on the double cylindrical shell. The annular plates are treated as axial forces, circumferential forces, radial forces and axial moments acting on the shells, which relate to displacements of the shells. Splints are simplified as poles an the reverse forces of splints are deduced which induce the force term in the vibration equation. The coupled vibration equation of sound, fluid and structure is solved. Theoretical results of radiated power, radial quadratic velocity and radiation efficiency are presented. In numerical analysis, the effect of connection is discussed, and the different results between the two connection typrs are analyzed in detail. It is concluded that the tighter the connection between the inner and outer shells is, the higher the sound radiation power is.