| 涡电流热效应对Terfenol-D棒材动态响应的影响 |
Alternative Title | Heading effect of eddy current on the dynamic behavior of Terfenol-D rod
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| 谭艺明 |
Thesis Advisor | 郑晓静
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| 2008-06-05
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Degree Grantor | 兰州大学
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Place of Conferral | 兰州
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Degree Name | 硕士
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Keyword | 超磁致伸缩
Terfeno-D
涡电流
有限元
热效应
动态响应
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Abstract | 超磁致伸缩材料作为一种新型的智能材料具有很多优越性,特别是良好的温度特性使其在众多的功能材料里备受瞩目。而由于超磁致伸缩材料不仅对磁场和预应力,同时也对温度变化十分敏感,因此,温度也是对磁致伸缩材料性能产生影响的一个关键因素。Terfenol-D作为执行器的主要成分,常处于时变磁场的工作环境下,因此在棒材横截面会有涡电流产生。涡电流会导致棒材内部的温度升高,如果涡电流产生的热无法及时通过热传递,热对流等方式得以耗散,就会影响棒材的动态响应。为了证明涡电流产生的热效应对超磁致伸缩棒材位移输出造成影响,本文首先由Maxwell 方程组出发,推导出棒材横截面涡电流控制方程和温度场控制方程,并推导出其有限元形式,求出棒材内横截面上的涡电流及涡电流引起的温度变化量的数值解,再将其带入磁致伸缩棒材的一维热本构,通过数值计算得出涡电流热效应对超磁致伸缩棒材动态响应的影响。由结果可以看出,涡电流的热效应可以使得棒材振动的振幅,平衡位置,共振频率,共振振幅等发生很大的变化。最后,为了减小涡电流的影响,将棒材沿轴向切割,用有限元方法计算得出切割后棒材横截面上的涡电流及温度场,由结果可以看出通过有效切割棒材,可以减小涡电流的热影响。 |
Other Abstract | Giant magnetostrictive material (GMM) is a kind of new type of smart material, which exhibits many outstanding advantages——especially its good temperature property makes it become the focus of attention. Since magnetostrictive material is sensitive not only to magnetic field and initial stress, but also to temperature, temperature becomes a crucial factor for affecting the magnetostriction performance. Terfenol-D, as the main element of actuator, generally works under the time-changing magnetic fields, thus eddy current and increasing temperature is induced inside it. If the heat produced by eddy current cannot be released in manner of heat conduction and thermal convection, it can influence dynamic behavior of Terfenol-D rod. In order to prove the displacement of the Terfenol-D rod caused by temperature increase induced by eddy current, the governing equations of the eddy current and temperature of Terfenol-D rod is drawn based on Maxwell equations, and the corresponding numerical simulations are conducted in this paper. Taking the temperature difference into Zheng-Sun model, we can get the dynamic behavior of Terfenol-D rod considering the affect of eddy current. The results show that even under low magnetic field, the difference of amplitude and equilibrium position of vibration, and resonant amplitude and resonant frequency caused by eddy current is distinct. In order to reduce the effect of eddy current in the dynamic behavior of Terfenol-D rod, FEM method is used to calculate the eddy current and temperature inside slotted Terfenol-D rod in the last of this paper, the results show that the effect of temperature induced by eddy current can be effectively diminished by slotting the rod. |
URL | 查看原文
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Language | 中文
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Document Type | 学位论文
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Identifier | https://ir.lzu.edu.cn/handle/262010/225880
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Collection | 土木工程与力学学院
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Recommended Citation GB/T 7714 |
谭艺明. 涡电流热效应对Terfenol-D棒材动态响应的影响[D]. 兰州. 兰州大学,2008.
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