一种隔离损伤的桁架结构性态识别方法

A STRUCTURAL STATE IDENTIFICATION METHOD FOR TRUSS STRUCTURES WITH SEPARATED DAMAGE

结构损伤的准确识别是结构健康监测的重要内容,由于识别的模型需要实时修正,使得结构整体刚度矩阵的更新和分解往往占用大量时间。该文基于隔离非线性理论,提出了一种隔离损伤的桁架结构性态识别方法。该方法将截面的应变分解成弹性应变和损伤应变,从截面刚度退化角度定义材料损伤,将表征损伤的刚度矩阵从整体矩阵中隔离出来,实现模型中损伤隔离,在迭代计算时避免了结构整体刚度矩阵的实时更新和分解,只需对规模较小表征损伤的刚度矩阵进行更新和分解,提高了损伤识别的求解效率。最后,以某实际钢桁架桥为例,对其主桁弦杆的损伤识别进行了数值模拟研究,设计了两种静力荷载工况对该方法进行验证。结果表明:当桁架结构发生局部损伤时,该方法可以准确高效地识别出发生损伤的位置和程度。

The accurate identification of structural damage is an important part of structural health monitoring.The identified model usually needs to be modified in real-time,which costs substantial computational effort because of the factorization of global stiffness matrix.In this paper,a new method of state identification for truss structures is presented based on the theory of inelasticity-separated method,in which the total strain of the cross section is decomposed into elastic strain and damage strain,and the material damage is evaluated by stiffness degeneration.The concept of the proposed method is that the stiffness matrix related to the damage of the model is segregated from the global stiffness matrix,and only the stiffness matrix with small scale is updated and factorized for local damage problems in the whole computation process.Thus,the calculation efficiency can be improved greatly for damage identification of truss structures.Finally,an actual steel truss bridge was taken as example,and the damage identification of the main truss strings were studied by numerical simulation.Two conditions of static loads were designed to verify the proposed method.The results show that the method can accurately and efficiently identify the location and extent when of the structural damage when it occurs in local domains.