温度影响下基于主成分分析和模态柔度的结构异常检测

李苗;黄天立;任伟新;

振动与冲击 ›› 2011, Vol. 30 ›› Issue (5) : 83-87.

PDF(1983 KB)
PDF(1983 KB)
振动与冲击 ›› 2011, Vol. 30 ›› Issue (5) : 83-87.
论文

温度影响下基于主成分分析和模态柔度的结构异常检测

  • 李苗1,2;黄天立1,2; 任伟新1,2
作者信息 +

PCA and modal flexibility-based structural novelty detection under temperature variations

  • LI Miao1,2; REN Wei-xin1,2
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文章历史 +

摘要


摘 要:在基于振动的结构损伤识别中,很多结构动力学的参数可用作损伤特征参数,如共振频率、振型、模态柔度等。结构损伤会引起损伤特征参数发生改变,但环境因素和运营条件的影响也会使这些特征参数发生变化,而且这种变化往往会掩盖结构自身损伤所引起的特征参数变化。如何剔除或减少诸多环境因素的影响,得到结构本身的真实状况(有损或无损),成为了桥梁损伤检测和健康监测中的一个关键问题。选用对结构损伤较为敏感的模态柔度作为损伤特征参数,通过数值模拟算例对比分析了结构局部损伤和温度变化对模态柔度的影响;对结构在不同状态下的模态柔度进行主成分分析,用残差建立其统计分布模式,用统计模式识别的方法识别模式差异,实现考虑环境因素影响的结构异常检测。结果表明,若不考虑温度对模态柔度的影响,易对桥梁结构的健康状况产生误判;运用基于主成分分析的结构异常检测方法可有效剔除温度对模态柔度的影响,实现结构异常的检测。


Abstract

eAbstract: Vibration-based SHM detects damage of structure through changes in vibration features, such as natural frequencies, mode shapes and modal flexibility. Modal parameters are not only affected by damage in structure, but also environmental and operational conditions. Compared to changes in the modal parameters induced by environmental and operational effect, those by local damage in structure could be much smaller. The subtle changes caused by delicate damage in structure may be masked because of such effect. To get real condition of structure, it is highly necessary to eliminate effect of environmental and operational condition on modal parameters. Modal flexibility was chosen as damage parameter for its sensitivity to damage. Via numerical model of simply supported beam, effect of local structure damage and temperature on modal flexibility was analyzed comparatively. After principal component analysis (PCA) being applied to modal flexibility under different conditions, statistical distribution patterns of structure were established on the residual errors of the PCA models. The structure novelty under environmental variations can be diagnosed by recognizing difference between the patterns using method of statistical pattern recognition. It’s demonstrated that false damage diagnosis may occur without considering effect of environmental variations; PCA-based novelty detection ffectively eliminate temperature influences on modal flexibility and provides indication of novelty for structure.

关键词

主成分分析 / 异常检测 / 温度影响 / 模态柔度

Key words

principal component analysis / novelty detection / temperature effect / modal flexibility

引用本文

导出引用
李苗;黄天立;任伟新;. 温度影响下基于主成分分析和模态柔度的结构异常检测[J]. 振动与冲击, 2011, 30(5): 83-87
LI Miao;REN Wei-xin;. PCA and modal flexibility-based structural novelty detection under temperature variations[J]. Journal of Vibration and Shock, 2011, 30(5): 83-87

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