自由阻尼结构损耗参数的换算方法

Conversion Method for Loss Factor of Unconstrained Damping Structures

在自由阻尼结构理论的基础上,建立了不同自由阻尼结构之间的结构损耗因子换算关系。针对自由阻尼板、壳结构开展了阻尼测试,换算结果与测试结果一致性良好,验证了换算方法的有效性。同时开展了换算系数和误差放大因子的仿真分析。仿真结果表明:对于弹性模量较高的阻尼层,换算系数随厚度比变化较小,换算精度较高;对于弹性模量较低的阻尼层,换算系数随厚度比变化较大,换算精度较低。建议阻尼层比目标基材层厚,且换算基材厚度小于目标基材厚度的2倍。该换算方法可用于预估一些难以测量的自由阻尼结构损耗参数,为大型简单圆柱壳结构敷阻尼层后损耗参数的获得以及多种阻尼层在大型圆柱壳结构上抑振性能的评比提供参考方案。

Based on theoretical loss factor′s formula of damping structure,a conversion method for the loss factor of different unconstrained damping structures is proposed.The damping tests are carried out on a damping plate and damping shell.The experimental results are compared with the results from the conversion method in order to prove the effectiveness of the conversion process.The conversion coefficient change with thickness ratio and error amplification factor are both analyzed in the process of loss factor calculation.The simulation results show that the conversion coefficient change with height ratio is bigger for damping material with a small elastic modulus than for damping material with a large elastic modulus,and the conversion data is more accurate for damping material with a larger elastic modulus.In order to improve precision,the thickness of damping materials should be bigger than that of the target backing material,and the thickness of conversion backing should be smaller than twice thickness of target backing.The unmeasured loss factor of the structure can be obtained through the conversion method.It achieves the goal of acquiring the loss factor of the damping structure,which is difficult to be measured in practice.This method provides a referable solution to acquisition of the loss factor of large damping cylindrical shells and vibration suppression effect comparison of various damping layers on large damping cylindrical shells.