基于柔度曲率曲线拟合的薄板结构损伤识别研究

Damage Identification of Thin Plate-Type Structures Based on the Flexibility Curvature Curve Fitting

提出了基于柔度曲率多项式曲线拟合的损伤识别方法,并用该方法对薄板结构进行损伤研究。采用有限元软件ANSYS进行模态分析,得到损伤薄板的模态振型和固有频率,进而得到X方向和Y方向柔度曲率,然后分别在X方向和Y方向进行多项式曲线拟合。基于拟合值与原始值的差值构造新的损伤指标。数值算例的结果表明,基于柔度曲率多项式曲线拟合的方法相比仅采用柔度曲率矩阵的方法能够更好地进行平板损伤定位,同时相比柔度曲率差等需要结构损伤前后模态数据的损伤识别方法,该方法不需要用到结构损伤前的模态数据,可以运用于难以获得健康结构的模态振型数据的结构损伤识别中。

A method of damage identification based on the flexural curvature polynomials curve fitting was presented and the method was then used to study the damage of thin plate structures. The modal shapes and natural frequencies of the damaged thin plate were obtained by the modal analysis using the finite element software ANSYS, and the flexibility curvatures in X-direction and Y-direction were provided. Then they were fitted with polynomial curves in the direction of X and Y axis. Based on the difference between the fitting values and the original values, a new damage index was proposed. The numerical results show that the method based on the flexibility curvature polynomial curve fitting can identify the damage position of the plate more accurately than the methods which only use the flexibility curvature matrix. Comparing with other methods, in the method it is not necessary to have the knowledge about the vibration modes of the original structure, so it can identify the damage cases where it is difficult to get the modal data in healthy state of the structure.