This paper aims to provide an overview of the experimental and simulation works focused on the detection, localisation and assessment of various defects in pipes by applying fast-screening guided ultrasonic wave techniques that have been used in the oil and gas industries over the past 20 years. Major emphasis is placed on limitations, capabilities, defect detection in coated buried pipes under pressure and corrosion monitoring using different commercial guided wave (GW) systems, approaches to simulation techniques such as the finite element method (FEM), wave mode selection, excitation and collection, GW attenuation, signal processing and different types of GW transducers. The effects of defect parameters on reflection coefficients are also discussed in terms of different simulation studies and experimental verifications.

Detection, Localisation and Assessment of Defects in Pipes Using Guided Wave Techniques: A Review.

Development of ultrasonic guided wave inspection methodology for steam generator tubes of prototype fast breeder reactor.

The accumulation of fouling within a structure is a well-known and costly problem across many industries. The build-up is dependent on the environmental conditions surrounding the fouled structure. Many attempts have been made to detect fouling accumulation in critical engineering structures and to optimize the application of power ultrasonic fouling removal procedures, i.e., flow monitoring, ultrasonic guided waves and thermal imaging. In recent years, the use of ultrasonic guided waves has been identified as a promising technology to detect fouling deposition/growth. This technology also has the capability to assess structural health; an added value to the industry. The use of ultrasonic guided waves for structural health monitoring is established but fouling detection using ultrasonic guided waves is still in its infancy. The present study focuses on the characterization of fouling detection using ultrasonic guided waves. A 6.2-m long 6-inch schedule 40 carbon steel pipe has been used to study the effect of (Calcite) fouling on ultrasonic guided wave propagation within the structure. Parameters considered include frequency selection, number of cycles and dispersion at incremental fouling thickness. According to the studied conditions, a 0.5 dB/m drop in signal amplitude occurs for a fouling deposition of 1 mm. The findings demonstrate the potential to detect fouling build-up in lengthy pipes and to quantify its thickness by the reduction in amplitude found from further numerical investigation. This variable can be exploited to optimize the power ultrasonic fouling removal procedure.

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Characterization of the Use of Low Frequency Ultrasonic Guided Waves to Detect Fouling Deposition in Pipelines

Pipeline structures are important structural components that cannot be replaced in actual engineering applications. Damage to a pipeline structure will create substantial safety hazards and economic losses in a project. Therefore, it is extremely important to study damaged pipeline structures. In this paper, L(0,2) mode guided waves are used to identify, locate, and image single and double defects in straight pipe structures. For the case where there is a single defect in the straight pipe section, the influence of different excitation frequencies on the reflection coefficient of L(0,2) modal guided wave is studied, and the optimal excitation frequency of L(0,2) guided wave is 70 kHz when single damage is determined. For the case of double defects in the straight pipe section, the double-defect size, the distance between the defects, and the relative defect positions are studied, and the influence of the defect recognition effect is analyzed. The propagation path of the ultrasonic guided wave in the double-defect pipe section is analyzed. Finally, the effectiveness of the three-point axial positioning method and damage imaging method is verified by the single-defect tube segment ultrasonic guided wave flaw detection experiment.

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Research on Pipeline Damage Imaging Technology Based on Ultrasonic Guided Waves

Long-range ultrasonic guided waves are widely used for the detection of defect founded in the long distance pipeline. Numerical simulation of guided wave propagation is considered for an experimental pipe with various forms of defects. The pipe is subjected to the propagation of the torsional guided wave . Numerical models are constructed for a sample pipe without defect and two sample pipes with two different types of defects: a notch and a notch with a hole. The desired T(0, 1) guided wave is simulated by a special excitation pressure function applied to one end of the pipe, which spreads via shearing motion parallel to the circumferential direction. Finite element software ANSYS is used to build 3D solid and finite element models of the sample pipes and perform full transient analysis. The simulation results allow obtaining information on the amplitude and the transit time of the impulse reflected from the defect and from the end of the pipe. The results also include the investigation of influence of the length and depth of the notch on the stress-strain state of the pipe.

Ping Men

Papers

Modeling Three-dimensional Ultrasonic Guided Wave Propagation and Scattering in Circular Cylindrical Structures using Finite Element Approach