共查询到19条相似文献,搜索用时 171 毫秒
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尺寸与表面效应及其对微齿轮强度的影响 总被引:1,自引:1,他引:0
由于特征尺寸很小,微齿轮具有明显的表面效应和小尺寸效应,而这两种效应对微齿轮强度均有重要影响.简单介绍国内外用LIGA(Lithographie,Galvanoformung,Abformung)、微细电火花等技术和方法制作的典型的微齿轮器件;从塑性应变梯度理论出发,用近年来的一些实验结果说明金属材料在微米尺度具有明显的尺寸效应;分析微构件的表面效应及产生表面效应的分子间作用力;分析尺寸效应和表面效应对微齿轮齿根强度、齿面接触及齿面摩擦的影响. 相似文献
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在广泛阅读国内外文献基础上,叙述了分子动力学(Molecular Dynamics,MD)模拟法的基本思想和步骤,对MD法在微/纳尺度接触问题的应用进行了综述.最后,指出MD法在研究微/纳尺度接触问题的局限性,提出一种更为精确的研究微/纳尺度接触问题的方法——多尺度耦合法. 相似文献
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微电子机械系统的力学特性与尺度效应 总被引:11,自引:0,他引:11
针对微电子机械系统(MEMS)材料的力学特性,工艺过程对力学特性的影响以及微执行器、微机器人的尺度效应等力学问题进行了研究。从力学角度提出了硅和常用的薄膜材料作为MEMS结构材料时应遵循的设计和加工原则,并系统地分析、归纳了静电、电磁、压电、形状记忆合金等各种微执行器的尺度效应特征。通过对机器蚂蚁、微型飞机、微型机器鱼等微机器人在微尺度下的动力学特性分析,得到微机器人在尺寸越小时越容易被驱动的结论,为设计和制作微机器人等复杂微系统提供了理论依据。 相似文献
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针对传统加工方法很难实现微机电系统(Micro electromechanical systems,MEMS)零部件高质量加工的问题,在微细加工技术研究基础上,提出采用飞秒激光双光子聚合加工技术加工标准渐开线微齿轮的方法.采用钛蓝宝石激光器自行搭建的飞秒激光双光子加工系统,能够输出波长为800 nm的飞秒激光用于双光子聚合加工,利用AutoCAD软件设计标准渐开线微齿轮,通过理论和试验两种方法研究激光功率与单个固化点尺寸之间的关系,进而研究扫描步距与加工精度和表面粗糙度之间的关系,结果表明,激光功率越小,加工分辨率越高;扫描步距越小,加工变形越大,但表面质量提高.采用优化后的加工工艺参数加工出高质量的标准渐开线微齿轮,其表面粗糙度Ra27.66 nm.因此,飞秒激光双光子加工技术能够为微齿轮或其他MEMS零部件的加工提供一条有效途径. 相似文献
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微线段齿廓齿轮的弯曲强度分析 总被引:8,自引:1,他引:7
介绍了微线段齿轮的形成原理,建立了微线段齿轮有限元计算的力学模型,论证了计算中的奇点问题,并提出相应的解决方案,用正交试验法设计了一组算例并用有限元法进行计算,从而说明微线段齿轮的弯曲强度确实要优于渐开线齿轮。 相似文献
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A feasibility study of microscale fabrication by ultrasonic-shoe centerless grinding 总被引:1,自引:0,他引:1
The present authors proposed a new centerless grinding technique, namely ultrasonic-shoe centerless grinding, which they validated experimentally in a previous study [Wu Y, Fan Y, Kato M, Wang J, Syoji K, Kuriyagawa T. A new centerless grinding technique without employing a regulating wheel. Key Eng Mater 2003;238–239:355–60]. Rather than a regulating wheel as in conventional centerless grinding, the new method uses a plate-shaped ultrasonic shoe, on the end face of which micro elliptic motion is generated, to support the workpiece and control its rotational motion. This enables the fabrication of a microscale cylindrical component less than 100 μm in diameter with an extremely large aspect ratio, which is extremely difficult to produce by conventional machining techniques. In the present study, in order to develop a novel technique for the fabrication of microscale cylindrical components, first an apparatus capable of microscale fabrication was designed and constructed based on the ultrasonic-shoe centerless grinding method. Following initial performance tests, the apparatus was tested by conducting a grinding run on a tungsten carbide test-piece, 0.6 mm in diameter and 15 mm in length. The result was a microscale cylindrical component, around 60 μm in diameter and 15 mm in length, with an aspect ratio of over 250, which validated the new technique proposed for microscale fabrication. 相似文献
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This article is the second in a four-part series of articles providing an overview of the challenges and opportunities in microscale additive manufacturing (AM) processes with applications in fabrication of high precision micro/nano-products. Laser-based microscale additive manufacturing processes are discussed this article. Compared to the other AM processes, laser-based processes provide several unique advantages, especially in terms of a wide variety of processable materials and high volumetric throughputs. The processes discussed in this paper can fabricate complex microscale features with minimum resolutions ranging from hundreds of nanometers to hundreds of microns. However, there are several fundamental limits and trade-offs which hinder the scalability of these processes. The paper discusses the limits to the materials, resolution, geometry, and volumetric throughput and proposes approaches to mitigate these limits and improve the scalability of laser-based microscale AM processes. 相似文献
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微线段齿轮基本齿形参数优化设计 总被引:4,自引:0,他引:4
提出了用正交回归法将优化设计的隐式目标函数,转化为显式目标函数的方法,建立了以微线段齿轮基本齿形参数为设计变量,齿根正应力为目标函数,以顶切,齿形畸变,齿顶圆压力角及零点数为约束条件的数学模型,给出了一组应用实例,用复合形法进行了计算,结果证明,效果明显。 相似文献