有限长,多层复合圆柱壳减振特性的研究

本文研究了有限长、多层复合圆柱壳的振动和减振特性.在两端自由边界条件下导出金属圆柱壳和粘贴阻尼材料形成的双层复合圆柱壳的振动方程和本征方程、解出本征值.计算出钢柱壳的固有振动频率以及复合圆柱壳振动的固有频率和阻尼系数值随阻尼层、金属层厚度比(h_2/h_1)的变化关系;计算并画出单、双层壳各阶振动模态的振型.为了验证与比较,还对钢柱壳和203~#-钢复合壳分别进行了实验测试,其结果与理论值相比:振动的固有频率吻合较好,阻尼系数值定性地符合.另外,阻尼系数随厚度比(h_2/h_1)变化的规律对工程应用有一定的指导意义.

Study of the Behavior in Reduction of Vibration and Sound of Composite Shells

The behavior in the reduction of vibration and sound of composite shells is studied. The governing defferential equations and the eigen equation of vibration of simple steel shell and double-layered cylindrical shell are derived under the condition of free-free end, and the eigen values are solved. The natural frequencies and damping factors of simple steel shell and double-layered shell (damping layer with different thickness) are numerically calculated and plotted against the thickness ratio of the damping layer to the metal base. The radial vibration mode shapes of various orders are.calculated and also plotted. The natural frequencies,damping factors and mode shapes are presented here also by the experiments. By comparison, the frequencies calculated agree with the experimental data and the damping factors coincide qualitatively. The rule of damping factors varying with (h_2/h_1) will provide some guidence to engineeirng applications.