Identification of Vibration Mode Shapes for a Bridge Deck under Ambient Vibration for the Health Monitoring

环境振动下桥面振动模态识别，用于健康监测

• 批准号: 12555132
• 负责人: FUJINO Yozo
• 金额: $ 8.26万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12555132/
• 关键词: Health monitoring; Laser doppler vibrometer; Ambient vibration; Inverse analysis; Modal properties

Vibration measurement is a powerful technique for structural health monitoring. Identification of high order vibration characteristics, especially vibration mode shapes, is needed to detect local damage in structures. However, in civil infrastructures, the difficulties of measuring spatial vibration and input excitation decrease the identification accuracy of these higher modes. Laser Doppler Vibrometer can be applied to reliable measurement of vibration of spatially large structures under microscopic vibrations such as ambient vibration. In this study, a spatial vibration measurement system is established, and non-stationary component in measured ambient vibrations are eliminated by sweeping the area of interest and repeatedly stacking the time histories recorded. In this way, mode shapes can be identified from these vibration measurement results without knowledge of input excitation.Vibration mode shapes of a bridge deck are identified using this laser vibration measurement system. However, in this case, lots of optical noise is contained in the time histories recorded for that made of concrete, because of the reduction of laser reflection quantity. To overcome this, for measurement points which are impossible to measure vibration, many sub-measurement points around that are set, and laser reflection quantity of each sub-measurement point is measured, respectively. By calculating the mean values, optimum measurement points that give maximum laser reflection are selected. Based on this function, the vibration mode shapes of the bridge deck are identified under ambient vibration, and it is verified experimentally that non-contact vibration measurement using Laser Doppler Vibrometer is possible to apply for bridge health monitoring.

振动测量是结构健康监测的有力手段。结构的局部损伤识别需要识别结构的高阶振动特征，特别是模态振型。然而，在民用基础设施中，空间振动和输入激励测量的困难降低了这些高次模态的识别精度。激光多普勒测振仪可用于大空间结构在环境振动等微观振动作用下振动的可靠测量。本研究建立了一套空间振动测量系统，通过对感兴趣区域进行扫频和对记录的时间历程进行反复叠加，消除了测量环境振动中的非平稳分量。这样，无需了解输入激励即可根据振动测量结果识别振型。使用该激光振动测量系统识别桥面的振动振型。然而，在这种情况下，由于激光反射量的减少，大量的光噪声包含在记录的混凝土的时间历程。为了克服这一点，对于不可能测量振动的测量点，在其周围设置许多子测量点，并且分别测量每个子测量点的激光反射量。通过计算平均值，选择给出最大激光反射的最佳测量点。基于该功能，识别了环境振动下桥面的振型，验证了激光多普勒测振仪非接触振动测量应用于桥梁健康监测的可行性。

项目成果

Fujino, Y., Kaito, K and Abe, M: "Detection of Structural Damage by Ambient Vibration Measurement Using Laser Doppler Vibrometer"Proceedings of The SPIE'S 6th Annual International Symposium on NDE for Health Monitoring and Diagnostics. (2001)

Fujino, Y.、Kaito, K 和 Abe, M：“使用激光多普勒振动计通过环境振动测量检测结构损坏”SPIE 第六届健康监测和诊断无损检测年度国际研讨会论文集。

Kaito, K., Abe, M. and Fujino: "An Experimental Modal Analysis for RC Bridge Decks Based on Non-Contact Vibration Measurement"Proceedings of The 19th International Modal Analysis Conference. 1561-1567 (2001)

Kaito, K.、Abe, M. 和 Fujino：“基于非接触式振动测量的 RC 桥面的实验模态分析”第 19 届国际模态分析会议论文集。

Kaito,K.,Abe,M.and Fujino,Y.: "An Experimental Modal Analysis for RC Bridge Decks Based on Non-Contact Vibration Measurement"Proceedings of The 19th International Modal Analysis Conference. 1561-1567 (2001)

Kaito,K.、Abe,M. 和 Fujino,Y.：“基于非接触式振动测量的 RC 桥面板实验模态分析”第 19 届国际模态分析会议论文集。

Kaito, K., Abe, M., Fujino, Y.: "An Experimental Modal Analysis for RC Bridge Decks Based on Non-Contact Vibration Measurement"Proceedings of The 19th International Modal Analysis Conference. 1561-1567 (2001)

Kaito, K.、Abe, M.、Fujino, Y.：“基于非接触式振动测量的 RC 桥面板实验模态分析”第 19 届国际模态分析会议论文集。

Kaito, K., Abe, M., Koide, K. and Fujino, Y: "Bridge Management Strategy for a Steel Plate Girder Bridge Based on Minimum Total Life Cycle Cost"Proceedings of The SPIE'S 6th Annual International Symposium on NDE for Health Monitoring and Diagnostics. (200

Kaito, K.、Abe, M.、Koide, K. 和 Fujino, Y：“基于最低总生命周期成本的钢板梁桥的桥梁管理策略”SPIE 第六届健康监测无损检测年度国际研讨会论文集