减振复合板阻尼测试样品模态分析及尺寸确定

Modal analysis and size determination of damping test sample for vibration damping composite plate

针对减振复合板样品在阻尼测试中样品尺寸标准不一,样品尺寸在确定时缺乏理论依据,无法确定测试样品尺寸的问题,利用有限元方法对减振复合板进行模态分析,用悬臂梁法进行阻尼实测。有限元模拟结果表明,在一定的宽度和厚度下,随着试样长度的增加,其1阶到6阶共振频率均出现降低的规律;在一定的长度和厚度下,随着样品宽度的增加,前4阶共振频率有略微增加的趋势;在一定的长度和宽度下,随着样品厚度的增加,1阶到3阶的共振频率基本保持稳定。实测结果表明,选取自由端长度为216mm、宽度为12.7mm的样品,利用2阶和3阶共振频率下的损耗因子进行阻尼表征较为合理。

For the vibration-damped composite plate samples,the sample size standards are different in the damping test,and the sample size lacks the theoretical basis in the determination,resulting in that the size of the test sample cannot be determined.The damped composite plate was modally analyzed by the finite element method.The cantilever beam method was used to measure the damping.The finite element simulation results showed that,with a certain width and thickness,the resonance frequency of the 1 st to 6 th order was decreasing with the increase of the length of the sample.Under a certain length and thickness,the first four order resonance frequencies slightly increased with the increase of the sample width.At a certain length and thickness,as the sample thickness increased,the resonance frequency of the 1 st to 3 rd order remained basically stable.The cantilever beam method was used to measure the damping.The measured results showed that the sample with a free end of 216 mm in length and a width of 12.7 mm was characterized by the loss factor at the 2 nd and 3 rd order resonance frequencies.