Among semi-destructive methods of measuring residual stresses in elastic materials, the blind hole-drilling strain-gage method is one of the best because it is simple, economical and accurate. It is based on the measurement of strains disturbed by machining a small diameter shallow hole in the test piece. The strains measured in three known directions permit the determination of the direction and magnitude of principal stresses and subsequently of any stress in any direction.
This thesis presents the investigation of residual stresses in the longitudinal direction of a welded fabricated steel tube of 22 inch diameter, relating to a series of holes drilled in one half of a circular section of the tube. An initial assumption, substantiated later, was the existence of a uniform field of residual stresses through the thickness of the tube. Several methods for determining calibration coefficients are documented. The values of longitudinal stresses once computed are presented in a smooth curve. A straight line approximation is reconnnended for use in further studies of the effects of residual stresses on failure loads.
| Identifer | oai:union.ndltd.org:pdx.edu/oai:pdxscholar.library.pdx.edu:open_access_etds-3579 |
| Date | 14 December 1977 |
| Creators | Tran, Chau Mong |
| Publisher | PDXScholar |
| Source Sets | Portland State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Dissertations and Theses |
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