Chapter 32 DRAFT: ILI, IN-DITCH AND PERMANENTLY INSTALLED TOOLS FOR STRESS/STRAIN IMAGING AND MONITORING

This paper addresses the ability to image and monitor strain (or stress), both residual and applied, in pipelines and other carbon steel structures such as risers and vessels. Strain (or stress) monitoring is needed to assess pipeline integrity after events such as ground motion, operating excesses, and prolonged operation in extreme environments. Three techniques are described: (1) an in-line-inspection (ILI) tool, (2) an in-ditch or above ground imaging method, and (3) a permanently installed approach. Each of these methods uses MWM sensors and MWM-Arrays to make non-contact measurements of the steel’s magnetic properties, which are then correlated to strain (or stress) in the material. Since the method uses magnetic fields, it can operate through non-conductive materials such as coatings and insulation. This work was funded in-part by JENTEK Sensors, Inc., the Department of Transportation (DOT), and end users. The opinions in this paper are those of the authors and not the sponsoring agencies.