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The effects of marine microorganisms on the mechanical properties of graphite/epoxy composites
| dc.creator | Puh, John Shui-Ming | |
| dc.date.accessioned | 2012-06-07T22:50:12Z | |
| dc.date.available | 2012-06-07T22:50:12Z | |
| dc.date.created | 1997 | |
| dc.date.issued | 1997 | |
| dc.identifier.uri | https://hdl.handle.net/1969.1/ETD-TAMU-1997-THESIS-P84 | |
| dc.description | Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item. | en |
| dc.description | Includes bibliographical references: p. 94-99. | en |
| dc.description | Issued also on microfiche from Lange Micrographics. | en |
| dc.description.abstract | The petroleum industry has expressed much interest in using tension leg platform for drilling at ocean depths of 2000 meters and deeper. However, due to the tremendous weight sensitivity of the platform, Polymeric composites have been considered to replace traditional steel materials for drilling and production risers, tethers, and other structures on the production platform. One reservation in using composites is the long term seawater effects on mechanical properties. Past research have mainly utilized distilled water or synthetic seawater. Natural seawater possesses many constituents including microorganisms that attach themselves to all submerged structures. In an effort to determine marine microorganism effects on composites, specimens with two different lay-ups were conditioned in natural seawater and then tensile tested while simultaneously monitored for acoustic emission activity. Graphite/epoxy composite specimens were fabricated from prepreg tape and then conditioned for 4 and I I months under stressed and unstressed conditions in air, sterile, and natural seawater. After conditioning, the specimens were weighed to determine weight gain due to moisture. The specimen ultimate tensile strengths and acoustic emission amplitude distributions were then correlated with the moisture absorption to determine the effects of marine microbial degradation. Ultimate tensile strength results showed that fiber properties were not degraded by the moisture absorption. This resulted in specimens conditioned in seawater having no worse properties than specimens conditioned in air. The acoustic emission results showed that since fibers were not affected by moisture, the high amplitude activity they produced were conditioning allowed more moisture to be absorbed; however, due to the fiber dominated nature of the specimens, ultimate tensile strengths were not affected. Long term moisture induced matrix plasticization had more of an effect than the moisture induced fiber/matrix interface degradation. In summary, the specimens conditioned in natural seawater had no worse properties than the specimens conditioned in sterilized seawater. | en |
| dc.format.medium | electronic | en |
| dc.format.mimetype | application/pdf | |
| dc.language.iso | en_US | |
| dc.publisher | Texas A&M University | |
| dc.rights | This thesis was part of a retrospective digitization project authorized by the Texas A&M University Libraries in 2008. Copyright remains vested with the author(s). It is the user's responsibility to secure permission from the copyright holder(s) for re-use of the work beyond the provision of Fair Use. | en |
| dc.subject | mechanical engineering. | en |
| dc.subject | Major mechanical engineering. | en |
| dc.title | The effects of marine microorganisms on the mechanical properties of graphite/epoxy composites | en |
| dc.type | Thesis | en |
| thesis.degree.discipline | mechanical engineering | en |
| thesis.degree.name | M.S. | en |
| thesis.degree.level | Masters | en |
| dc.type.genre | thesis | en |
| dc.type.material | text | en |
| dc.format.digitalOrigin | reformatted digital | en |
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