Repair of dents combined with gouges considering cyclic pressure loading
Conference
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OSTI ID:460684
- Stress Engineering Services, Inc., Houston, TX (United States)
- Kiefner and Associates, Inc., Worthington, OH (United States)
Mechanical damage is one of the primary causes of failures in pipe systems. A research program was developed in an effort to quantify the effects of dents with minor scratches on both the burst pressures and fatigue lives of pipelines. Gouges were installed in test specimens at 5% and 10% of the wall thickness, and then dents were installed with a bar placed longitudinally in these notched samples. Dent depths of 5, 10, 15 and 20% of the pipe diameter were studied. One of the primary objectives in this program was to provide pipeline operators with a basic understanding of first, how dent and gouge depths will effect their pipes, and secondly, which defects can be repaired and what is the best procedure for making those repairs. Grinding out the gouge was the restoration method selected for this study. Test specimens were typically tested in pairs so that comparisons could be made between repaired and unrepaired specimens. According to the burst test results, gouge depths of 10% or more combined with dents greater than 15% have burst strengths which are less than 72% SMYS; however, gouges which are less than 5% of the wall in conjunction with dents less than 10% have burst strengths which exceed 100% SMYS. The fatigue tests indicated that dents with gouges definitely act to reduce the fatigue life of pipes, with the level of dent and gouge depth being directly related to their life. In both types of testing, grinding was found to be a suitable method for strength and life restoration.
- OSTI ID:
- 460684
- Report Number(s):
- CONF-970146--; ISBN 1-890277-01-0
- Country of Publication:
- United States
- Language:
- English
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