结构阻尼的声衰减时间测量方法

Approach for Determining Structural Damping by Measurement of Sound Attenuation Time

针对结构阻尼的测量,通过分析平板的辐射声压,发现结构自由振动时的声压级的衰减率与平板的振动水平的衰减率相等。基于此提出了通过测量结构自由振动时的声衰减时间来计算结构损耗因子的测量方法,采用该方法及传统的测量方法测量得到的结构损耗因子在整个测试频率范围内基本相等。分析及实验结果表明,该方法正确可行,并且可实现结构阻尼的非接触测量。

A new method is presented to determine the structural damping.Through analyzing the radiation sound pressure of a plate,the attenuation ratio of the level of sound pressure is equal to that of the level of vibration when the structure vibrated freely.Based on the conclusion a valid method of determining structural damping through the measurement of sound attenuation time is presented.The structural loss factors,which are determined individually by using the new method and the traditional method,are almost equal to each other in the interested band of frequency.The analysis and experimentation show that the new method is correct,and can measure the damping of structure without contact.