Nondestructive residual stress mapping of damage in pipeline steel has been demonstrated as a new approach for pipeline integrity management. The handheld system for rapid characterization pipelines has been used on dents and wrinkles, two of the most common forms of mechanical deformation. The ability to compare residual stresses with design stresses will allow for a much more accurate criteria for use in fitness-for-service and improved modeling of pipeline stresses. As the capabilities of in-line inspection technologies continue to improve, operators are often faced with thousands of indications that require examination. Accurate assessment of residual stresses will provide a more effective method of combatting the most common form of pipeline failures, mechanical damage.
The residual stresses associated with the mechanical damage forms the basis for the nucleation and growth of cracks at areas with the highest residual stresses. Quantitative, real-time knowledge of the through-thickness residual stress levels associated with the mechanical damage will enable enhanced Risk-Based Inspection and drastically improve pipeline integrity. The development of a non-destructive, quantified residual stress measurement system to evaluate the damage severity on pipeline steels through the structural coatings (without any removal) will enable improved integrity assessment and reduce the number of unnecessary removal and replacement activities. The development of a real-time, through-thickness residual stress sensor to assess steel pipeline mechanical damage is presented in this paper.