The influence of dent imperfections on the elastic stress behavior of cylindrical shells
is explored. This problem is of central importance to the prediction of fatigue failure
due to dents in petroleum pipelines. Using an approximate technique called the
Equivalent Load Method, a semi-analytical model of two-dimensional dent stress
behavior is developed. In the three-dimensional situation, decreased dent localization,
in particular dent length, and increased dent depth are confirmed to cause dent stress
concentration behavior to shift from having a single peak at the dent center to having
peaks at the dent periphery. It is demonstrated that the equivalent load method
does not predict this shift in stress behavior and cannot be relied upon to analyze
relatively small, deep imperfections. The two stress modes of dents are associated
with two modes of dent fatigue behavior that have significantly different fatigue lives.
A method for distinguishing longer lived Mode P dents from shorter lived Mode C
dents based on two measured features of dent geometry is developed and validated.
An approach for implementing this analysis in the evaluation of real dents is also
suggested.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/37 |
| Date | 30 September 2004 |
| Creators | Rinehart, Adam James |
| Contributors | Keating, Peter B. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 3161259 bytes, 278937 bytes, electronic, application/pdf, text/plain, born digital |
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