结构损伤与荷载的快速同步识别方法研究

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振动与冲击 ›› 2013, Vol. 32 ›› Issue (2) : 33-38.

论文

结构损伤与荷载的快速同步识别方法研究

张青霞1,3, 段忠东2,3 Łukasz Jankowski4

作者信息 +

Fast simultaneous identification of structural damages and loads

Zhang Qingxia 1,3, Duan Zhongdong 2,3 Łukasz Jankowski4

Author information +

文章历史 +

摘要

本文仅以损伤因子为优化变量，提出一种结构损伤和荷载同步识别的方法。首先通过时域荷载识别的方法将未知荷载转化为损伤因子的函数，将近似荷载作用下的结构响应和实测响应的平方距离作为目标函数，从而降低了需要识别未知参数的数目；然后在目标函数的计算过程中，利用虚拟变形法（VDM）可进行结构快速重分析的思想，快速构造给定损伤因子下系统的脉冲响应，避免每步迭代重新集装系统矩阵，并通过荷载形函数方法进一步提高荷载识别的效率；最后利用二次多项式插值近似结构每个时刻的响应方法和推导对应目标函数的梯度表达式来提高优化搜索的速度。本文利用刚架模型进行数值模拟，准确识别了结构中柱子单元刚度损伤、附加质量以及梁上的未知移动荷载，并通过一个悬臂梁试验进一步验证所提出方法的准确性和可行性。

Abstract

A load and damage simultaneous identification method is proposed via taking in which only the damage factors are taken as the optimization variables. Firstly, unknown loads are converted into the function of the damage factors via the load identification method in time domain, such that the number of the optimizational is reduced. The optimization is performed by minimizing the square distance between the measured responses and the estimated responses corresponding to the estimated loads and the given damage factors. During the optimization, in order to increase the computational efficiency, Virtual distortion method (VDM) is employed, which is fast structural reanalysis method. Via VDM, the system impulse response of the damaged structure regard to the given damage factors is constructed efficiently and it avoids repetitively assembling the damaged structural parameters which is time-consuming. Further, the load shape function method is used to estimate unknown load which can improve the ill-conditioning problem of the inverse problem and also obviously reduce the computational work. At last, the optimization is further speeded up by interpolating the estimated structural responses using quadratic polynomial via which the expression of the gradient of the objective function can be obtained. In a numerical simulation of a three-span frame, a moving excitation and the damages including the stiffness-related damages and an additional mass are identified successfully with a 5% Gaussian noise pollution. And an experiment of a cantilever beam is performed to validate the accuracy and the feasibility of the proposed method.

导出引用

张青霞;段忠东;&#;ukasz Jankowski . 结构损伤与荷载的快速同步识别方法研究[J]. 振动与冲击, 2013, 32(2): 33-38

Zhang Qingxia;Duan Zhongdong;&#;ukasz Jankowski. Fast simultaneous identification of structural damages and loads[J]. Journal of Vibration and Shock, 2013, 32(2): 33-38