基于振动响应的耦合弦系统损伤检测

为解决具有相近频率和相重频率特征的多跨耦合弦系统的损伤检测问题,建立了耦合弦系统在外激励作用下的有限元运动方程.利用直接积分法计算了系统强迫振动响应,将弦的局部损伤模拟为单元面积的减少,推导了振动响应对弦单元面积的灵敏度,并利用此响应灵敏度进行弦的局部损伤识别.数值算例表明:此方法能快速准确地识别出耦合弦的局部损伤,并且对模拟的人工噪声不敏感.

Damage Detection in Coupled String System by Measured Dynamic Responses

Aiming at the damage detection for coupled string system with close and repeated natural frequencies, finite element method is chosen to analyze forced vibration of the coupled string system. The dynamic response sensitivity with respect to the physical parameter (elemental cross-sectional area) is then derived. In the inverse analysis, the local damages in the string are identified from dynamic response sensitivity-based finite element model updating method. It is found that the local damage can be identified successfully from several dynamic response measurements. The effect of artificial measurement noise on the identified results is also discussed. Thenumerical simulation shows that the proposed method is insensitive to the measurement noise and with higher accuracy.