Reflection of torsional T(0,1) guided waves from defects in pipe bends

Heinlein, Sebastian; Cawley, P.; Vogt, Thomas

doi:10.1016/j.ndteint.2017.09.007

Cited by 44 publications

(29 citation statements)

References 25 publications

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“…It is also affected by fluid in the pipe, so the torsional mode is more commonly used in practice. GWT using T(0,1) is most effective on straight sections achieving several tens of metres of inspection range but recent studies have evaluated its performance on bends [41].…”

Section: Guided Wave Inspectionmentioning

confidence: 99%

Monitoring of Critical Metallic Assets in Oil and Gas Industry Using Ultrasonic Guided Waves

Dhutti¹,

Lowe²,

Gan³

2019

Advances in Structural Health Monitoring

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This chapter presents advancements in structural health monitoring (SHM) using ultrasonic guided waves (UGW) technology for metallic structures to support their integrity and maintenance management. The focus is on pipelines and storage tanks, which are critical assets in the Oil and Gas industry, whose operational conditions can greatly accelerate damage mechanisms. Conventional routine inspections are both costly and time consuming and affect the plant reliability and availability. These operational and economic disadvantages have led to development of SHM systems which can be permanently installed on these critical structures to provide information about developing damage and optimise maintenance planning and ensure structural integrity. These technology advancements enable inspection without interruption to operations, and generate diagnosis and prognosis data for condition-based maintenance, hence increasing safety and operational efficiency. The fundamentals, architecture and development of such SHM systems for pipes and above ground storage tanks are described here.

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Section: Guided Wave Inspectionmentioning

confidence: 99%

Monitoring of Critical Metallic Assets in Oil and Gas Industry Using Ultrasonic Guided Waves

Dhutti¹,

Lowe²,

Gan³

2019

Advances in Structural Health Monitoring

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show abstract

“…Conventionally, guided wave testing (GWT) of pipelines using the fundamental torsional T(0,1) mode has been shown to reliably detect large corrosion-like defects, which result in around 2 − 5% cross-sectional area (CSA) loss 9 . Detection sensitivities for pipeline inspections can be improved by employing a monitoring configuration, which would typically involve permanently installing a ring of transducers at a specific location, allowing for the reliable detection of relatively smaller corrosion patches, with as little as 0.5 − 1% in CSA loss 10 .…”

Section: Introductionmentioning

confidence: 99%

“…In this way, a synthetic or hybrid dataset is generated and used to evaluate the damage detection capability, taking into account the effect of environmental variations on the response of the structure. This methodology has been successfully used to validate the damage detection Prepared using sagej.cls ability of permanently installed monitoring systems 10,12 .…”

Section: Introductionmentioning

confidence: 99%

Crack growth monitoring using fundamental shear horizontal guided waves

Chua

Cawley

2019

Structural Health Monitoring

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Monitoring cracks in critical sections of steel structures is a topic of growing interest. Existing high-frequency ultrasonic techniques have good detection sensitivities but poor inspection coverage, requiring an impractical number of transducers to monitor large areas. Low-frequency guided waves are used for corrosion detection in pipelines but are insufficiently sensitive for many crack detection applications. The sensitivity can be improved using higher frequencies and by placing the receiving transducers closer to the defect. This study evaluates the monitoring performance of an SH0 mode system at frequencies just below the high-order mode cut-off. Baseline subtraction with temperature compensation was applied to experimental data generated by a ring of transducers on a 6-in diameter pipe. It was found that the residual signals after baseline subtraction were normally distributed so the random fluctuations could be reduced by coherent averaging; it was thereby possible to reliably detect a 2 mm × 1 mm notch simulating a crack located one pipe diameter along the pipe from the transducer ring. The damage detection performance at different locations along the pipe was assessed by analysing receiver operating characteristic curves generated by adding simulated defects to multiple experimental measurements without damage. At a fixed standoff distance, the damage detection performance increases with the square root of the number of averaged signals and is also improved by averaging the signals received by transducers covering the main lobe of the reflection from the defect. When the defect is located more than about one pipe circumference from the transducer ring, the optimal performance is obtained by averaging across all the transducers in the ring, corresponding to monitoring the T(0,1) pipe mode. Therefore, an SH0 mode monitoring system has great potential for crack monitoring applications, particularly for welds in pipes.

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“…Guided waves, which are ultrasonic waves restricted by the boundaries of the solid waveguide during propagation [1], have been applied in the inspection of many industrial structures, such as pipes [2,3], rods [4], plates [5][6][7] and rails [8][9][10] with the advantages of long distance, full coverage and low cost [11]. The conversions between the electrical energy and mechanical energy are mainly involved in guide wave inspection, which are accomplished by the transducers as the key parts in the inspection system.…”

Section: Introductionmentioning

confidence: 99%

Signal Strength Enhancement of Magnetostrictive Patch Transducers for Guided Wave Inspection by Magnetic Circuit Optimization

Tang

Yang

et al. 2019

Applied Sciences

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Magnetostrictive patch transducers (MPT) with planar coils are ideal candidates for shear mode generation and detection in pipe and plate inspection with the advantages of flexibility, lightness and good directivity. However, the low energy conversion efficiency limits the application of the MPT in long distance inspection. In this article, a method for the enhancement of the MPT was proposed by dynamic magnetic field optimization using a soft magnetic patch (SMP). The SMP can reduce the magnetic resistance of the magnetic circuit, which increases the dynamic magnetic field intensity in the magnetostrictive patch during wave generation and restricts the induced dynamic magnetic field within the area around the coils for sensing during wave detection. Numerical simulations carried out at different frequencies verified the improvement of the dynamic magnetic fields by the SMP and influence of different affecting factors. The experimental validations of the signal enhancement in wave generation and detection were performed in an aluminum plate. The amplitude magnification could reach 12.7 dB when the MPTs were covered by the SMPs. Based on the numerical and experimental results, the SMP with a large relative permeability and thickness and close fitting between the SMP and coils were recommended when other application conditions were met.

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Reflection of torsional T(0,1) guided waves from defects in pipe bends

Cited by 44 publications

References 25 publications

Monitoring of Critical Metallic Assets in Oil and Gas Industry Using Ultrasonic Guided Waves

Monitoring of Critical Metallic Assets in Oil and Gas Industry Using Ultrasonic Guided Waves

Crack growth monitoring using fundamental shear horizontal guided waves

Signal Strength Enhancement of Magnetostrictive Patch Transducers for Guided Wave Inspection by Magnetic Circuit Optimization

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