The purpose of this study was to investigate the properties of air-textured aramid yarn (ATAY), in a single yarn composite (SYC), in a 3D woven fabric preform, and in a 3D preform composite. Yarn tensile tests demonstrated textured yarn was 70-77% lower in tensile strength, 82-85% lower in tensile modulus, and 60-190% higher in breaking strain than those of the control yarn. The results of SYC testing illustrated that the control yarn composite had only a 5% higher tensile strength, a 27% higher modulus, and 11% lower energy to break than the textured single yarn composite. Fabric tensile tests demonstrated a low initial modulus and a much larger secondary modulus for all 3D woven preforms. The ATAY fabric had a similar initial modulus and a much lower secondary modulus in the weft direction compared to the control fabric. The ATAY fabric had a significantly higher yield shear stress and strain, primary and secondary shear moduli, energy to yield point, and total energy absorbed to 4° than those of the control. With the same fiber volume fraction, the ATAY composite had a slightly lower tensile strength and modulus, but a 120% higher shear modulus, than the regular aramid yarn (RAY) composite. Unlike the RAY composite brittle failure behavior, the ATAY composite failed in a ductile manner with multiple diverting cracks propagating during failure. The ATAY composite had a much higher yield point in the 45° direction tensile test, a much higher softening point in the warp direction tensile test, and increased the interlaminar shear strength of a laminated composite by 37% as compared with the control.
| Identifer | oai:union.ndltd.org:NCSU/oai:NCSU:etd-06022003-205619 |
| Date | 05 June 2003 |
| Creators | Langston, Thomas Brice |
| Contributors | Dr. Yiping Qiu, Dr. Abdel Fahmy, Dr. Timothy Clapp |
| Publisher | NCSU |
| Source Sets | North Carolina State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://www.lib.ncsu.edu/theses/available/etd-06022003-205619/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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