基于模态柔度曲率差的弯管结构损伤识别

Damage Identification of Bend-Type Structure Based on Modal Flexibility-Curvature and Difference

为对弯管结构进行无损检测,结合有限元模拟和实验模态分析方法,对具有不同位置和程度的损伤弯管结构进行研究,计算和分析其模态柔度曲率差,探讨模态分析方法在弯管结构损伤检测中的适用性。研究结果表明:弯管结构的模态柔度具有方向性,弯管所在平面x,y方向柔度求解的模态柔度曲率差不能对弯管进行损伤识别;垂直弯管所在平面z方向柔度不仅可以对弯管进行单处、多处的损伤定位,而且可以对同一位置的损伤程度进行定量分析。

To effectively detect the bend-type structure,the finite element method(FEM)and experimental modal analysis(EMA)are employed to generate the modal flexibility of the bend-type structure.Then the modal flexibility is used to compute modal flexibility-curvature and difference by using the central difference method.Different severities,locations and the number of damage are simulated by additional quality in the intact bend-type to verify the modal flexibility-curvature and difference generated by both FEM and EMA.The results show that the modal flexibility of bend-type should have the direction.In addition,it can be obtained that using the plane x,y direction to solve the modal flexibility curvature difference cannot bend damage identification methods for damage identification.However,using the vertical pipe where the plane z direction of the bending flexibility,the multiple damage location,and quantitative analysis for the extent of injury to the same location can be carried out.