The fatigue response of mechanical properties and life due to constant stress amplitude tension-tension(T-T)cyclic loading at elevated temperature in nanocomposite APC-2 laminates was investigated. From the basic testing the total amount of 1% by weight of SiO2 spreaded in the interfaces was proved optimally. Related experiments on unidirectional nanocomposite APC-2 laminates were completed, including static tension tests in [0]16¡B[30]16¡B[45]16¡B[60]16 and [90]16 and T-T cyclic tests in [0]16¡B[45]16 and [90]16 specimens at room temperature. After obtaining experimental data, such as ultimate strength and elastic modulus, which were found improved significantly, and then comparing with the basic theory of mechanics of composites, rule of mixtures was adopted to estimate the properties of cross-ply and quasi-isotropic nanocomposite APC-2 laminates and found the largest errors were within 25%. In the consideration of heterogeneous and anisotropic properties of the matrix and the reinforced fibers in nature, the results are reasonably acceptable. On the other hand, the S-N curves according to the experimental data of the fatigue tests were plotted. The vertical axis shows the nondimensional stress level, i.e., the applied maximum stress normalized by ultimate strength at room temperature, and the horizontal axis represents the logarithm of applied cycles. The S-N curves at room and elevated temperatures were also expressed by curve fitting from top to bottom as temperature increasing from RT to 150¢J for both cross-ply and quasi-isotropic nanocomposite laminates. However, when applied maximum stress was normalized by the corresponding ultimate strength, the positions of S-N curves were reverse, i.e., the curves were shown from bottom to top as temperature increasing from RT to 150¢J. That strongly hints us the resistance to fatigue at elevated temperature in both lay-ups of nanocomposite laminates is indeed significantly improved.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0712105-153812 |
| Date | 12 July 2005 |
| Creators | Huang, Yu-Hsin |
| Contributors | none, Ming-Hwa R. Jen, none, Ming Chen |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0712105-153812 |
| Rights | not_available, Copyright information available at source archive |
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