Damage assessment through changes in mode shapes due to non-proportional damping
Damage assessment through changes in mode shapes due to non-proportional damping
复制标题
通过非比例阻尼引起的振型变化进行损伤评估
DOI：
10.1088/1742-6596/628/1/012019
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
C. Valente
中科院分区：
文献类型：
--
作者：
F. Iezzi;D. Spina;C. Valente
在动力学领域，模态参数常用于结构损伤评估。通常，假设不同状态之间的模态参数的变化作为损伤的度量。频率很容易识别，但在某些情况下，它们对损害不敏感，而且它们主要是一个全球性的措施。相反，振型更适合于损伤定位，但它们通常很难准确识别。能量耗散和阻尼随损伤而增加。该特征是稳定的，并且具有单调行为，因此，阻尼可以自信地用作损伤评估的替代或补充措施，尽管其识别的准确性。然而，阻尼本身具有与频率相同的缺点。阻尼和振型的联合使用是一种有效的损伤识别方法。在真实的世界中，阻尼是非比例型的，并且所测量的振型是复杂的。假设损伤的增加引起非比例阻尼的修正和模态复杂度的变化。两种不同结构状态之间的模态复杂程度可以通过适当的指标来识别损伤。介绍并讨论了一些此类指标。理论和伪实验数据的有效性和灵敏度的损伤指标进行了测试。
Modal parameters are often used for the structural damage assessment in the dynamic field. Usually, the changes in the modal parameters between different states are assumed as measures of damage. The frequencies are easy to identify, but in some circumstances they are not sensitive to damage and moreover they are mainly a global measure. On the contrary, the mode shapes are more suited for damage localization, but they are generally hard to identify accurately. The energy dissipation, and hence the damping, increases with damage. This feature is stable and has a monotonic behaviour, therefore, damping can be confidently used as an alternative or complementary measure for damage assessment in spite of the accuracy of its identification. However, the damping by itself suffers of the same drawbacks as the frequencies. The joint use of damping and mode shapes is an effective procedure for the damage identification. In the real world the damping is of nonproportional type and the measured mode shapes are complex. It is assumed that an increase of damage causes a modification of non-proportional damping and a variation of the modal complexity. The extent of modal complexity between two different structural states can be used to identify the damage through appropriate indicators. A number of such indicators is introduced and discussed. The effectiveness and sensitivity of the damage indicators are tested on theoretical and pseudo-experimental data.