基于振动响应的耦合杆系统损伤识别

Damage Identification in a Coupled Rod System from Measured Dynamic Responses

基于响应灵敏度分析法对两跨耦合杆系统的损伤识别问题进行了研究。建立了耦合杆系统的有限元运动方程,利用状态空间法计算系统在外激励下的响应。将系统的局部损伤模拟为杆单元抗拉刚度的减少,推导了响应对单元抗拉刚度的灵敏度。并利用此响应灵敏度进行系统的局部损伤识别。数值算例表明,文中方法能快速准确地识别出耦合杆的局部损伤,并且对模拟的人工噪声不敏感。说明该方法具有一定的工程应用前景。

A new damage identification method for a coupled rod system with close and repeated natural frequencies is presented. The equation of motion for the coupled system is established from finite element analysis. The dynamic responses of the system are obtained from state-space method. And the dynamic responses of the system are used for damage detection. The local damage of the system is modeled by a reduction in the elemental tensile stiffness. The dynamic response sensitivity with respect to the damage parameter （elemental tensile stiffness） is then derived. In the inverse analysis, the local damages in the system are identified from dynamic response sensitivity-based finite element model updating method. It is found that the local damage （s） can be identified successfully from several dynamic response measurements. The effect of artificial measurement noise on the identified results is also discussed. Numerical simulation shows that the proposed method is insensitive to the measurement noise and with very good accuracy. This shows that the proposed method has the potential for real application.