A new standing-wave testing system for bridge structure nondestructive damage detection using electromagnetic wave

2014 ◽  
Vol 10 (2) ◽  
pp. 157-165 ◽  
Author(s):  
Haitao Xiao ◽  
Jianan Qin ◽  
Harutoshi Ogai ◽  
Xiuchen Jiang
Keyword(s):  
Electromagnetic Wave ◽  
Damage Detection ◽  
Standing Wave ◽  
Testing System ◽  
Bridge Structure ◽  
Nondestructive Damage Detection

Elimination of outlier measurements for damage detection of structures under changing environmental conditions

2021 ◽  
pp. 147592172199847
Author(s):  
William Soo Lon Wah ◽  
Yining Xia
Keyword(s):  
Damage Detection ◽  
Multiple Regression ◽  
Natural Frequencies ◽  
Detection Method ◽  
Detection Methods ◽  
Structure Model ◽  
Bridge Structure ◽  
Beam Structure ◽  
Dependent Variables ◽  
The Difference

Damage detection methods developed in the literature are affected by the presence of outlier measurements. These measurements can prevent small levels of damage to be detected. Therefore, a method to eliminate the effects of outlier measurements is proposed in this article. The method uses the difference in fits to examine how deleting an observation affects the predicted value of a model. This allows the observations that have a large influence on the model created, to be identified. These observations are the outlier measurements and they are eliminated from the database before the application of damage detection methods. Eliminating the outliers before the application of damage detection methods allows the normal procedures to detect damage, to be implemented. A multiple-regression-based damage detection method, which uses the natural frequencies as both the independent and dependent variables, is also developed in this article. A beam structure model and an experimental wooden bridge structure are analysed using the multiple-regression-based damage detection method with and without the application of the method proposed to eliminate the effects of outliers. The results obtained demonstrate that smaller levels of damage can be detected when the effects of outlier measurements are eliminated using the method proposed in this article.

Assessment of Damage in Metallic Plates by Ultra-Wideband Guided Electromagnetic Waves

2021 ◽  
Author(s):  
Vittorio Memmolo ◽  
Jochen Moll ◽  
Duy Hai Nguyen ◽  
Viktor Krozer ◽  
Jakob Holstein ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Damage Detection ◽  
Electromagnetic Waves ◽  
Signal To Noise Ratio ◽  
Damage Index ◽  
Ultra Wideband ◽  
Wideband Signals ◽  
Index Approach ◽  
Electromagnetic Waveguide ◽  
Spatial Locations

Abstract Guided electromagnetic wave propagation using ultra-wideband signals is a barely new approach for damage detection. However, still many challenges are present, including the way to deal with the GHz domain signals and the physics behind the interaction phenomena enabled by any type of flaw. The present work proposes a feasibility analysis for a structural health monitoring system employing permanently integrated microwave sensors. This setup allows to interrogate the structure continuously using multiple transmitters and multiple receivers when the electromagnetic waveguide is established. To this end, a metallic plate is equipped with a dielectric waveguide patch attached to the structures’ surface. To validate the detectability of damage, a reversible defect is modeled through removable bolts accessible from the other surface of the plate. The experiments are carried out considering different bottom holes at different spatial locations of the plate. In addition, concurrent measurements are adopted to characterize the noise level within the signal. The characteristic changes of electromagnetic wave signals are caught using a damage index approach returning whether the defect can be detected sensitively or not. Different coupling conditions are used to let the guided electromagnetic waves propagate and interact with underlaying structure. The results show that this approach can be adopted for damage detection with a reasonable signal to noise ratio, especially when the waveguide is well coupled. In addition, both transmission and reflection loss can be monitored reliably.

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