变时基原理在裂缝损伤梁动态检测中的应用

Application of Variable Time Base Theory to Dynamic Detection of Beam with Crack Damage

提出运用变时基原理解决脉冲激振试验中的频率分辨率与时域波形精度的问题,同时解决了激励与响应之间,特征时间与特征频率的差异太大的问题。结合裂缝简支梁的脉冲激振试验,表明变时基原理能够得到较为完善的激励与响应的时域和频域波形。将激振试验结果用频率变化平方比法来进行裂缝损伤位置检测,找到了裂缝损伤的位置。结果表明,变时基原理能够较好解决脉冲激振试验中的频率分辨率与时域波形精度的问题,拓展了脉冲激振试验的适用范围。

Variable Time Base (VTB) theory is presented to improve the frequency resolution and the time domain precision. The existing error problem of exciting and response, eigentime and eigenvalue are resolved. The time domain and frequency domain form of exciting and response is acquired from simple-supported-beam exciting test. The ratio of frequency difference square is provided to determine crack damage location. It is demonstrated that VTB theory could rightly extracted the problem of frequency resolution and time domain form precision and thus extends the application field of impulse vibration tests.