大型复杂结构损伤识别两步法研究

Study on Two-step Damage Detection Methods of Large and Complex Structures

基于模型修正技术及模态柔度曲率差方法提出了一种解决大型复杂结构损伤识别问题的两步法。首先运用基于模型修正的损伤识别方法进行模糊识别,通过建立带约束边界非线性最小二乘目标函数,极小化结构实测模态与解析模态之间的误差,将损伤识别问题转化为优化问题,并采用信赖域方法求解该优化问题,识别出损伤所属单元组。然后运用模态柔度曲率差方法,对损伤进行精确定位。对某导弹发射台骨架的数值仿真及试验研究结果表明,该损伤识别两步法识别效果较为理想,为解决大型复杂结构的损伤识别问题提供了新思路。

A new method for complex structures damage detection was proposed based on model updating and modal flexibility curvature difference techniques herein.The method have two steps.First,the method based on model updating was used for preparatory detection.The detection problem was transformed into an optimization problem in this method.An objective function was defined as an nonlinear least-squares problem with bound-constrains and for detection of the location of structural damage by minimizing the sum of differences between the experimental and analytical modal data.The trust-region approach was then used to solve the minimization problem.The method based on modal flexibility curvature difference was then used for detect the location of structural damage accurately.Finally,the proposed method was applied for damage detection on the frame of a launch platform.The simulation and experimentatal results show that the proposed method is suitable well for damage detection on such complex structures.