Development of an EMAT in-Line Inspection System for Detection, Discrimination, and Grading of Stress Corrosion Cracking in Pipelines Progress Report (open access)

Development of an EMAT in-Line Inspection System for Detection, Discrimination, and Grading of Stress Corrosion Cracking in Pipelines Progress Report

This report describes prototypes, measurements, and results for a project to develop a prototype pipeline in-line inspection (ILI) tool that uses electromagnetic acoustic transducers (EMATs) to detect and grade stress corrosion cracking (SCC). The introduction briefly provides motivation and describes SCC, gives some background on EMATs and guided ultrasonic waves, and reviews promising results of a previous project using EMATs for SCC. The experimental section then describes lab measurement techniques and equipment, the lab mouse and prototypes for a mule, and scan measurements made on SCC. The mouse was a moveable and compact EMAT setup. The prototypes were even more compact circuits intended to be pulled or used in an ILI tool. The purpose of the measurements was to determine the best modes, transduction, and processing to use, to characterize the transducers, and to prove EMATs and mule components could produce useful results. Next, the results section summarizes the measurements and describes the mouse scans, processing, prototype circuit operating parameters, and performance for SH0 scans. Results are given in terms of specifications--like SNR, power, insertion loss--and parametric curves--such as signal amplitude versus magnetic bias or standoff, reflection or transmission coefficients versus crack depth. Initially, lab results indicated magnetostrictive transducers using …
Date: February 1, 2005
Creator: Aron, Jeff; Jia, Jeff; Vance, Bruce; Chang, Wen; Pohler, Raymond; Gore, Jon et al.
System: The UNT Digital Library