Application of Direct Electromagnetic Lamb Wave Generation to Gas Pipeline Inspection

Abstract

It is well established that elastic waves may be generated in a metal without physical contact through the reaction of a static magnetic field and dynamically induced eddy currents. The technique can significantly reduce the time needed in certain ultrasonic inspection problems because there is no need to re-establish a mechanical bond at each point of measurement. However, it has not yet received sufficient attention to determine its potential in actual industrial problems. This paper describes a feasibility study of the application of direct electromagnetic transduction to the inspection of gas pipelines from within the pipe. Experimental results are presented demonstrating the generation and detection of 130 kHz antisymmetric Lamb waves in 3/8 in. thick steel plate and pipe. The sensitivity of the process to various design parameters is discussed as well as the amplitude of signals reflected from defects. The experimental results for transduction and reception efficiencies are compared to a theoretical model.

Water and Wastewater Pipe Nondestructive Evaluation and Health Monitoring: A Review

“…The ability of guided waves to locate cracks and notches in pipes has been demonstrated in several laboratory works [63,[66][67][68][69]. One of the advantages of GUWs in pipelines is that the theoretical foundation of wave propagation is well formulated (see, e.g., [19]).…”

The upcoming revolution in ultrasonic guided waves

“…carried out the angular profile calculations and the phased array focusing technique for torsional guided wave propagation in hollow cylinders [21]. If the angular profiles show that ultrasonic energy is naturally concentrated at a circumferential location at a particular propagation distance, this phenomenon, which is called "natural focusing," can be used to improve pipeline inspection [22,23].…”

Experiences in the Use of Guided Ultrasonic Waves to Scan Structures

“…Under the support of the Pipeline Research Committee of the American Gas Association, a "pig" was developed to mspect buned natural gas pipelines using gmded modes, propagatmg araund the circumference [2,[4][5][6]. Figure 2 shows an early Iabaratory prolotype [5] and a weil developed robot used m field tests [2].…”