Pipeline Safety

Our goal is to provide standard test methods and critical data to the pipeline industry to improve safety and reliability. Of particular interest is the testing of high-strength pipeline steels, which could enable higher volume gas transport and reduce energy costs. However, characterizing the ductile fracture properties of these materials is difficult, limiting their use due to safety concerns. We are developing new methods to test these materials to enable pipeline designers to better predict fracture dynamics and make better informed material selections.

Running crack in a buried pipeline. 

We are adapting the Crack Tip Opening Angle (CTOA) method to testing pipeline steels. CTOA is becoming one of the more widely accepted properties for characterizing fully plastic fracture, especially for running ductile cracks in pipes. It can be measured directly from the crack opening profile and can be related to the geometry of the fracturing pipe. In cases where there is a large degree of stable-tearing crack extension during fracture, CTOA can measure fracture resistance. Our research focuses on improving the optical imaging technique for determining the opening angle.

Specimen configuration for the CTOA test.

In addition to CTOA test development, we also measure the fatigue properties of different pipeline steels at full thickness to provide data on predicted pipeline performance. Specimens are machined directly from the pipeline longitudinal axis. To date, the fatigue behavior of six pipeline steels have been investigated.

(Left) Fatigue test of pipeline section and (right) aged pipe sample.