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为了研究脆性材料单晶硅原子级的纳米振动切削加工去除机制,应用分子动力学,通过改变刀具椭圆振动切削的模式,进行单晶硅纳米振动切削仿真.仿真结果表明,主切削力和法向力的变化趋势总体上呈现正弦曲线变化,并且已加工表面不同深度的亚表层存在残余应力;同时在不同切削模式下,由于刀具法向的振幅增加,使得法向力和残余应力增大;当刀具通过已加工表面时,残余应力随着亚表层深度降低而减弱;刀具法向振幅高于主切削力方向振幅时,法向力峰值高于主切削力峰值,已加工表面亚表层没有明显驰豫现象. 相似文献
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单晶Cu材料纳米切削特性的分子动力学模拟 总被引:3,自引:0,他引:3
建立了单晶Cu纳米切削的三维分子动力学模型,研究了不同切削厚度下纳米切削过程中工件缺陷结构和应力分布的规律.纳米切削过程中,在刀具的前方和下方形成变形区并伴随缺陷的产生,缺陷以堆垛层错和部分位错为主.在纳米尺度下,工件存在很大的表面应力,随着切削的进行,工件变形区主要受压应力作用,已加工表面主要受拉应力作用.随着位错在晶体中产生、繁殖及相互作用,工件先后经过弹性变形——塑性变形——加工硬化——完全屈服4个变形阶段,随后进入新的循环变形.结果表明:工件应力-位移曲线呈周期性变化;切削厚度较小时,工件内部没有明显的层错产生,随着切削厚度的增大,工件表面和亚表层缺陷增加;切削厚度越大,对应应力分量值越小. 相似文献
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采用宏/微结合双驱动的少自由度并联进给结构,给出了一种光栅拼接装置设计算法.宏动部分是5PTS-1PPS型并联机构,采用步进电机驱动滚珠丝杠形式的进给机构;微动部分是5TSP-1PPS型并联机构,采用压电陶瓷驱动柔性铰链形式的进给机构;二者串联构成光栅拼接机构.计算了宏动部分和微动部分的并联机构自由度,利用并联机构运动学的逆解推导出该装置的控制算法,并根据控制算法进行了宏动、微动机构点位控制的运动学仿真.为了提高机构的定位精度,分析了机构的系统误差并提出了误差修正方法.最后,将以上算法应用到光栅拼接装置中.实验结果表明:宏动部分最大移动定位误差为3.6 μm,最大转动定位误差为4.4 μrad;微动部分最大移动定位误差为0.06 μm,最大转动定位误差为1.2 μrad;基本满足光栅拼接系统的精度要求. 相似文献
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聚晶金刚石加工刀具在中国的研究与发展 总被引:4,自引:0,他引:4
详细介绍了聚晶金刚石(PCD)木工刀具在中国的研究发展情况,并对中国木材加工工业的现状,PCD木工刀具的使用特性以及主要的研究方向进行了分析,指出PCD刀具在木工行业有着广阔的应用前景。 相似文献
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Non-contact atomic force microscopy(nc-AFM) atomic-scale imaging process of monocrystalline silicon surface using capped single-wall carbon nanotube tip is simulated by molecular dynamic method. The simulation results show that the nc-AFM imaging force mainly comes from the C-Si and C-C chemical covalent bonding forces, especially the former, the nonbonding Van der Waals force change is small during the range of stable imaging height. When the tip-surface distance is smaller than the stable imaging height, several neighboring carbon atoms at the tip apex are attracted, and some of them jump onto the sample surface. Finally the tip apex configuration is destroyed with the tip indenting further. 相似文献
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基于多晶材料的微观拓扑结构,从多晶Cu纳米压痕中晶粒内部、晶界面、三叉晶界和顶点团等4类微观结构与缺陷结构的配位数、内应力、原子势能等方面,研究了压痕表面位错缺陷的演化机制。结果表明:当高维数的微观结构承载压应力时,与其邻近的低维数微观结构表现为拉应力,且更低维数的微观结构(顶点团)更易表现为拉应力;位错缺陷形核时其原子具有较高的内应力与原子势能,扩展时其边缘的不完全位错原子内应力高于内部堆垛层错原子内应力;位错形核与扩展和内应力的累积与释放具有相似的方向性,首先扩展至低维数的顶点团、三叉晶界,而后传递至高维数的晶界面并止于晶界面。 相似文献
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Yuhai LI 《等离子体科学和技术》2022,24(6):64012
Low-pressure air plasma cleaning is an effective method for removing organic contaminants on large-aperture optical components in situ in the inertial confinement fusion facility. Chemical reactions play a significant role in plasma cleaning, which is a complex process involving abundant bond cleavage and species generation. In this work, experiments and reactive molecular dynamics simulations were carried out to unravel the reaction mechanism between the benchmark organic contaminants of dibutyl phthalate and air plasma. The optical emission spectroscopy was used to study the overall evolution behaviors of excited molecular species and radical signals from air plasma as a reference to simulations. Detailed reaction pathways were revealed and characterized, and specific intermediate radicals and products were analyzed during experiments and simulation. The reactive species in the air plasma, such as O, HO2 and O3 radicals, played a crucial role in cleaving organic molecular structures. Together, our findings provide an atomic-level understanding of complex reaction processes of low-pressure air plasma cleaning mechanisms and are essential for its application in industrial plasma cleaning. 相似文献