基于广义柔度矩阵的井架钢结构损伤识别

A generalized flexibility matrix-based damage identification method for derrick steel structures

摘要:

钻机井架结构在生产过程中会因各种原因而出现不同程度的损伤及破坏，为解决复杂工作环境下石油钻井井架结构健康监测中损伤识别问题，提出了一种基于广义柔度矩阵的井架结构损伤识别方法。相比于柔度矩阵方法，广义柔度矩阵仅需前几阶低阶固有频率及相应的模态振型便可确保计算的精度。在构建损伤控制方程的过程中，采用矩阵分块模式求解方法，与传统方法中需将单元刚度矩阵扩充整体刚度矩阵维数相比较，所提出的求解方法只需针对单元刚度矩阵的行数进行相应扩充，而列数不变，因此从计算量的统计角度分析可大大降低构建损伤识别控制方程的计算量。最后，以实际工程中的K型井架钢结构为例，结果显示对于不同的损伤位置及程度，该方法均具有良好的识别效果，可用于其他大型结构的损伤诊断或健康监测。

Abstract:

The drilling rig derrick structure will be damaged and destroyed to different degrees due to various reasons during the production process. In order to solve the problem of damage identification in the health monitoring of oil derrick structure in a complex working environment， a method of damage identification of derrick structure based on the generalized flexibility matrix is proposed. Compared with the flexibility matrix method， the generalized flexibility matrix only needs the first few low-order intrinsic frequencies and corresponding modal shapes to ensure the accuracy of the calculation. In the process of constructing the damage control equations， the matrix block solving method is adopted. Compared with the traditional method that requires the expansion of the element stiffness matrix to the overall stiffness matrix dimensions， the proposed solving method only needs to expand the number of rows of the element stiffness matrix accordingly， while the number of columns remains unchanged， so that the computation requirements for constructing the damage identification control equations can be greatly reduced. Finally， taking the K-type steel derrick structure as a numerical example， the results show that the method has great recognition effects for different damage locations and degrees and can be used for damage diagnosis or health monitoring of other large structures.