幅频特性对结构损伤的敏感性

以悬臂梁作实验模型，测量其自由端加速度对该点激振荷载的幅频特性曲线，求得 具有不同深度切口悬臂梁的前两阶固有频率和幅频特性曲线的前两个峰值对切口的灵敏 度。结果表明，与基频相比幅频特性曲线的第一峰值对悬臂梁切口的灵敏度大约高出一 个数量级，第二固有频率也比基频对切口的灵敏度要高一些。还用模态综合法算出切口 悬臂梁的前两阶固有频率和幅频特性曲线的前两个峰．结果与实验能较好地吻合．

Sensitivity of Amplitude Frequency Characteristic to Structure Damage

A cantilever beam is used as an experimental., Amplitude frequency characteristic of acceleration versus dynamic loading at its free end is measured. Two first. principal frequencies and peak values of amplitude frequency characteristic of grooved cantilever with various depth groove are investigated. Experimental results show that the variant rate of height of the first peak of amplitude frequency characteristic with changing groove depth is almost ten times as that of the first principal frequency. The variant rate of the second principal frequency is also higher than that of the first principal frequency. Two first principal frequencies and peaks of amplitube frequency characteristic are computed by structure synthesis method for demonstrating the experimental results. The computed results coincide with the experimental ones quite well.