Vibration properties of civil structures, which are commonly analysed for damage detection, are affected by changing environmental and operational conditions, and most notably are subjected to bilinear effects from changing ambient temperature conditions. Therefore, damage detection in structures during the past decade has focused on eliminating the effects of these changing environments that affect the vibration properties of the structures. Several methods have been proposed in the literature to tackle the non-linear effects from changing environments. However, these methods can only analyse systems (e.g. natural frequency–environmental and operational system) that have an incremental change in relationship; they cannot model the bilinear effects from the changing temperature conditions, which may lead to false alerts. Hence, a damage detection method is proposed in this paper to tackle the piecewise effects from changing temperature conditions. The method makes use of a Gaussian mixture model to separate the different effects acting on the structures and uses principal component analysis for data processing. The method is applied to the Z24 Bridge, in Switzerland, which was subjected to bilinear effects from changing temperature conditions. The results obtained demonstrate that the proposed method successfully takes into account the piecewise effects to indicate the presence of damage.

中文翻译：

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使用 PCA 在温度条件下检测损坏 - Z24 Bridge 的应用

土木结构的振动特性通常被分析用于损伤检测，它受到环境和运行条件变化的影响，最明显的是受到环境温度条件变化的双线性效应的影响。因此，在过去十年中，结构损伤检测的重点是消除这些影响结构振动特性的变化环境的影响。文献中提出了几种方法来解决不断变化的环境带来的非线性影响。然而，这些方法只能分析具有增量关系变化的系统（例如固有频率-环境和运行系统）；他们无法模拟温度条件变化的双线性效应，这可能导致错误警报。因此，本文提出了一种损伤检测方法来解决温度条件变化带来的分段效应。该方法利用高斯混合模型来分离作用在结构上的不同影响，并使用主成分分析进行数据处理。该方法应用于瑞士的 Z24 桥，该桥受到温度条件变化的双线性影响。获得的结果表明，所提出的方法成功地考虑了分段效应来指示损坏的存在。该方法应用于瑞士的 Z24 桥，该桥受到温度条件变化的双线性影响。获得的结果表明，所提出的方法成功地考虑了分段效应来指示损坏的存在。该方法应用于瑞士的 Z24 桥，该桥受到温度条件变化的双线性影响。获得的结果表明，所提出的方法成功地考虑了分段效应来指示损坏的存在。