Lamb mode selection for accurate wall loss estimation via guided wave tomography

2014 ◽  
Author(s):  
P. Huthwaite ◽  
R. Ribichini ◽  
M. J. S. Lowe ◽  
P. Cawley
Keyword(s):  
Mode Selection ◽  
Guided Wave ◽  
Loss Estimation ◽  
Wave Tomography ◽  
Wall Loss ◽  
Selection For ◽  
Lamb Mode

scholarly journals An Investigation on a Quantitative Tomographic SHM Technique for a Containment Liner Plate in a Nuclear Power Plant with Guided Wave Mode Selection

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2819 ◽  
Author(s):  
Yonghee Lee ◽  
Younho Cho
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Elastic Wave ◽  
Nuclear Power ◽  
Guided Waves ◽  
Mode Selection ◽  
Wave Mode ◽  
Guided Wave ◽  
Element Analysis ◽  
Wave Tomography

The containment liner plate (CLP) in a nuclear power plant is the most critical part of the structure of a power plant, as it prevents the radioactive contamination of the surrounding area. This paper presents feasibility of structural health monitoring (SHM) and an elastic wave tomography method based on ultrasonic guided waves (GW), for evaluating the integrity of CLP. It aims to check the integrity for a dynamic response to a damaged isotropic structure. The proposed SHM technique relies on sensors and, therefore, it can be placed on the structure permanently and can monitor either passively or actively. For applying this method, a suitable guided wave mode tuning is required to verify wave propagation. A finite element analysis (FEA) is performed to figure out the suitable GW mode for a CLP by considering geometric and material condition. Furthermore, elastic wave tomography technique is modified to evaluate the CLP condition and its visualization. A modified reconstruction algorithm for the probabilistic inspection of damage tomography algorithm is used to quantify corrosion defects in the CLP. The location and shape of the wall-thinning defects are successfully obtained by using elastic GW based SHM. Making full use of verified GW mode to Omni-directional transducer, it can be expected to improve utilization of the SHM based evaluation technique for CLP.

scholarly journals Improving accuracy through density correction in guided wave tomography

2016 ◽  
Vol 472 (2186) ◽  
pp. 20150832 ◽  
Author(s):  
P. Huthwaite
Keyword(s):  
Guided Waves ◽  
Low Frequency ◽  
Region Of Interest ◽  
Density Variation ◽  
Pressure Vessels ◽  
Guided Wave ◽  
Wave Tomography ◽  
Wall Loss ◽  
Improving Accuracy ◽  
The Waves

The accurate quantification of wall loss caused by corrosion is critical to the reliable life estimation of pipes and pressure vessels. Traditional thickness gauging by scanning a probe is slow and requires access to all points on the surface; this is impractical in many cases as corrosion often occurs where access is restricted, such as beneath supports where water collects. Guided wave tomography presents a solution to this; by transmitting guided waves through the region of interest and exploiting their dispersive nature, it is possible to build up a map of thickness. While the best results have been seen when using the fundamental modes A0 and S0 at low frequency, the complex scattering of the waves causes errors within the reconstruction. It is demonstrated that these lead to an underestimate in wall loss for A0 but an overestimate for S0. Further analysis showed that this error was related to density variation, which was proportional to thickness. It was demonstrated how this could be corrected for in the reconstructions, in many cases resulting in the near-elimination of the error across a range of defects, and greatly improving the accuracy of life estimates from guided wave tomography.

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