Improved Defect Detection Using Adaptive Leaky NLMS Filter in Guided-Wave Testing of Pipelines
Ultrasonic guided wave (UGW) testing of pipelines allows long range assessments of pipe integrity from a single point of inspection. This technology uses a number of arrays of transducers, linearly placed apart from each other to generate a single axisymmetric wave mode. The general propagation rout...
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| Format: | Article |
| Language: | English |
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MDPI AG
2019-01-01
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| Series: | Applied Sciences |
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| Online Access: | http://www.mdpi.com/2076-3417/9/2/294 |
| _version_ | 1818142101388394496 |
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| author | Houman Nakhli Mahal Kai Yang Asoke K. Nandi |
| author_facet | Houman Nakhli Mahal Kai Yang Asoke K. Nandi |
| author_sort | Houman Nakhli Mahal |
| collection | DOAJ |
| description | Ultrasonic guided wave (UGW) testing of pipelines allows long range assessments of pipe integrity from a single point of inspection. This technology uses a number of arrays of transducers, linearly placed apart from each other to generate a single axisymmetric wave mode. The general propagation routine of the device results in a single time domain signal, which is then used by the inspectors to detect the axisymmetric wave for any defect location. Nonetheless, due to inherited characteristics of the UGW and non-ideal testing conditions, non-axisymmetric (flexural) waves will be transmitted and received in the tests. This adds to the complexity of results’ interpretation. In this paper, we implement an adaptive leaky normalized least mean square (NLMS) filter for reducing the effect of non-axisymmetric waves and enhancement of axisymmetric waves. In this approach, no modification in the device hardware is required. This method is validated using the synthesized signal generated by a finite element model (FEM) and real test data gathered from laboratory trials. In laboratory trials, six different sizes of defects with cross-sectional area (CSA) material loss of 8% to 3% (steps of 1%) were tested. To find the optimum frequency, several excitation frequencies in the region of 30–50 kHz (steps of 2 kHz) were used. Furthermore, two sets of parameters were used for the adaptive filter wherein the first set of tests the optimum parameters were set to the FEM test case and, in the second set of tests, the data from the pipe with 4% CSA defect was used. The results demonstrated the capability of this algorithm for enhancing a defect’s signal-to-noise ratio (SNR). |
| first_indexed | 2024-12-11T11:10:25Z |
| format | Article |
| id | doaj.art-0c840e2dad01446592438b9d03f71179 |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-12-11T11:10:25Z |
| publishDate | 2019-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-0c840e2dad01446592438b9d03f711792022-12-22T01:09:33ZengMDPI AGApplied Sciences2076-34172019-01-019229410.3390/app9020294app9020294Improved Defect Detection Using Adaptive Leaky NLMS Filter in Guided-Wave Testing of PipelinesHouman Nakhli Mahal0Kai Yang1Asoke K. Nandi2Department of Electronic and Computer Engineering, Brunel University London, Uxbridge UB8 3PH, UKTWI, Granta Park, Cambridge CB21 6AL, UKDepartment of Electronic and Computer Engineering, Brunel University London, Uxbridge UB8 3PH, UKUltrasonic guided wave (UGW) testing of pipelines allows long range assessments of pipe integrity from a single point of inspection. This technology uses a number of arrays of transducers, linearly placed apart from each other to generate a single axisymmetric wave mode. The general propagation routine of the device results in a single time domain signal, which is then used by the inspectors to detect the axisymmetric wave for any defect location. Nonetheless, due to inherited characteristics of the UGW and non-ideal testing conditions, non-axisymmetric (flexural) waves will be transmitted and received in the tests. This adds to the complexity of results’ interpretation. In this paper, we implement an adaptive leaky normalized least mean square (NLMS) filter for reducing the effect of non-axisymmetric waves and enhancement of axisymmetric waves. In this approach, no modification in the device hardware is required. This method is validated using the synthesized signal generated by a finite element model (FEM) and real test data gathered from laboratory trials. In laboratory trials, six different sizes of defects with cross-sectional area (CSA) material loss of 8% to 3% (steps of 1%) were tested. To find the optimum frequency, several excitation frequencies in the region of 30–50 kHz (steps of 2 kHz) were used. Furthermore, two sets of parameters were used for the adaptive filter wherein the first set of tests the optimum parameters were set to the FEM test case and, in the second set of tests, the data from the pipe with 4% CSA defect was used. The results demonstrated the capability of this algorithm for enhancing a defect’s signal-to-noise ratio (SNR).http://www.mdpi.com/2076-3417/9/2/294adaptive filteringleaky normalized mean squareultrasonic guided wavespipeline inspectionSNR enhancementsignal processing |
| spellingShingle | Houman Nakhli Mahal Kai Yang Asoke K. Nandi Improved Defect Detection Using Adaptive Leaky NLMS Filter in Guided-Wave Testing of Pipelines Applied Sciences adaptive filtering leaky normalized mean square ultrasonic guided waves pipeline inspection SNR enhancement signal processing |
| title | Improved Defect Detection Using Adaptive Leaky NLMS Filter in Guided-Wave Testing of Pipelines |
| title_full | Improved Defect Detection Using Adaptive Leaky NLMS Filter in Guided-Wave Testing of Pipelines |
| title_fullStr | Improved Defect Detection Using Adaptive Leaky NLMS Filter in Guided-Wave Testing of Pipelines |
| title_full_unstemmed | Improved Defect Detection Using Adaptive Leaky NLMS Filter in Guided-Wave Testing of Pipelines |
| title_short | Improved Defect Detection Using Adaptive Leaky NLMS Filter in Guided-Wave Testing of Pipelines |
| title_sort | improved defect detection using adaptive leaky nlms filter in guided wave testing of pipelines |
| topic | adaptive filtering leaky normalized mean square ultrasonic guided waves pipeline inspection SNR enhancement signal processing |
| url | http://www.mdpi.com/2076-3417/9/2/294 |
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