Thesis
The effects of interference fit pins in glass fiber reinforced plastic joints
Washington State University
Master of Science (MS), Washington State University
2011
Handle:
https://hdl.handle.net/2376/103198
Abstract
The effects of inserting interference fit stainless steel pins into glass fiber reinforced plastics (GFRP) with 6.35 mm drilled holes will be investigated experimentally. Mechanical properties of the composite samples will be determined, to include: bearing strength, fatigue life, and maximum useful interference fit percentage. Interference fit percentages in the range from 0% to 1% will be examined for effectiveness. The static bearing strength and fatigue properties of the pin-loaded GFRP composites with interference-fit will then be compared to samples with transition-fits. Fractography for micro-failure modes of each sample will be examined using an optical microscopy. It is found that interference fit pins positively affect the bearing strength and fatigue life of pin loaded GFRP composites. Bearing strength rises marginally, while fatigue performance of all specimens tested is radically increased by the introduction of interference. This is due to the highly compressed fibers and matrix in the vicinity of the interference fit pin. These stressed fibers and matrix materials stabilize and limit pin displacement during cyclic loading. This leads to a decrease in the initial displacement necessary to attain maximum applied fatigue load by up to 25 microns. Interference fit percentages (I%) in the 0.6% range performed the best in almost v all coupon types, and showed the greatest benefit in fatigue testing. I=1% pins, on the other hand, show a great deal of scatter, with some samples performing well and others failing early due to pin insertion damage. Comparisons of the vacuum infution (VI) and hand layup (HL) processed laminates show that fatigue enhancement is achieved for VI coupons due to higher fiber volume. The fatigue behavior of the hybrid (HYB) processed samples shows failure characteristics of both HL (nettension) and VI (bearing failure). The major finding from the HL laminate was that the HL side failure induced total failure of the sample. This makes the fatigue life performance of the HYB coupons closer to that of HL than that of VI coupons.
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Details
- Title
- The effects of interference fit pins in glass fiber reinforced plastic joints
- Creators
- Daniel John Hennigan
- Contributors
- Dave Kim (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Mechanical and Materials Engineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525199101842
- Language
- English
- Resource Type
- Thesis