基于频响函数谱能量的网架损伤识别方法

DAMAGE DETECTION FOR RETICULATED STRUCTURES BASED ON SPECTRUM ENERGY OF FREQUENCY RESPONSE FUNCTION

  • 摘要: 网架结构多用于大型公共设施,一旦发生工程意外,后果严重。网架损伤区域的确定将对损伤的精确定位提供极大的便利。该文在加速度谱能量理论的基础上提出了频响函数谱能量的概念,将平稳白噪声激励下的节点加速度谱能量用频响函数重构,进而获得节点的频响函数谱能量。针对能量分布曲面提出了其几何特征指标,并以该指标的百分比变化来确定损伤的区域。该方法避免将频率和振型作为输入参数,能够指示损伤的范围。数值计算表明了该文所提方法的可行性。针对识别过程中的干扰现象,提出了“对称效应”的概念。

     

    Abstract: Reticulated structures are often applied in large scaled public facility, whose failure will lead to heavy losses. Identification of damage zone will facilitate significantly damage diagnosis. The concept of spectrum energy of frequency response function was proposed in this paper based on spectrum energy of acceleration response. Spectrum energy of acceleration response under white noise excitation can be reconstructed with frequency response function, thus nodes spectrum energy of frequency response function can be obtained. Geometrical characteristic index for energy distribution surface was defined; whose value can indicate, to some extent, damage degree. The proposed method does not require natural frequencies and mode shapes as input parameters. Numerical analysis of a reticulated structure demonstrated the feasibility of the method proposed. ‘Symmetry effect’ was observed in damage detection.

     

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