共查询到20条相似文献,搜索用时 62 毫秒
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《机械制造与自动化》2016,(3):31-33
应用数控渐进成形设备,针对铝合金锥形件进行了试验研究。通过改变成形中的润滑方式、工具头形状、工具头直径、进给量等工艺参数,并对成形后的试验件表面粗糙度和表面形貌进行测量和分析,研究成形参数对零件表面质量的影响。实验结果如下:球头工具头成形的零件表面质量优于圆柱形工具头,大直径的工具头成形零件的表面质量要好于小直径的工具头,层进给量越小,零件表面质量越好,固体润滑剂相比于液体润滑剂对5754铝合金成形的零件表面质量影响较小。 相似文献
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王淮欣 《精密制造与自动化》2014,(3)
控制臂现阶段成形工艺多、生产效率低、劳动强度大,并且材料的利用率低于50%。通过对控制臂三维几何模型的建立,采用辊锻制坯工艺,结合控制臂的形状特点,合理的设计弯曲模。利用有限元数值模拟软件DEFORM-3D对模锻成形过程进行数值模拟,对终锻模进行了优化,提出了带阻力墙终锻模,通过数值模拟分析得出合格的锻件,并且材料利用率提高至70%。 相似文献
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我厂生产的3NB80泥浆泵,其空气包系受压容器。为提高零件的机械强度,延长使用寿命,工艺由原铸钢件整体浇铸改为锻钢件上下壳体焊接。图1为空气包下壳体零件图,图2为下壳体锻件图。该零件几何形状类似厚壁封头,特点是外径尺寸大、孔深、壁厚、中间有高凸缘,形状特殊,锻造工艺性差,成形难。针对上述问题,我们进行了多次试验,最后在3吨蒸汽锤上采用模锻成形工艺,获得成功。实践证明,合理的出坯尺寸和锻模,是该零件锻造成形的关键。下壳体锻造分四火完工:一、二火:将钢锭切除烧冒口,然后锻成图3形状尺寸的坯件。边缘厚薄要均匀,否则翻边成形后的 相似文献
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雷达波导件塑性成形工艺分析及有限元数值模拟 总被引:1,自引:0,他引:1
以雷达上的波导件为研究对象,针对传统加工工艺的缺点以及工件形状特点,提出挤压成形工艺方案。利用有限元分析软件DEFORM对该工件的关键成形工序—反挤压过程进行刚塑性有限元数值模拟研究。通过数值模拟,观察到在不同压下测量时毛坯的等效应力、等效应变云图及挤压力与行程图,得到其金属流动规律,为合理设计模具和验证工艺提供依据。 相似文献
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《机械科学与技术》2015,(12):1956-1960
根据汽车桥壳胀-压复合成形工艺压制过程的基本步骤,通过ABAQUS有限元模拟软件对汽车桥壳压制过程进行数值模拟。研究了汽车桥壳压制过程中模具运动方式以及预制坯内部压强大小对桥壳成形件质量的影响,确定了最佳的桥壳压制模具运动方式以及预制坯内部压强的大小,并进一步分析了理想桥壳成形件壁厚分布情况。模拟结果表明:汽车桥壳胀-压复合成形工艺压制过程中,当压制模具同时运动且预制坯内部压强为30 MPa时桥壳成形件的成形质量最佳。在最佳成形条件下,桥壳成形件中间壁厚最薄,最薄壁厚为3.2 mm且大于初始设计最薄厚度,桥壳的轮廓清晰、过渡圆角大小合适且没有破裂或飞边失效,满足汽车桥壳的设计要求与使用要求。 相似文献
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基于类等势场的粉末高温合金盘件预成形设计及有限元模拟 总被引:3,自引:1,他引:3
为了提高产品的质量和工作效率并降低生产成本,需对预制坯进行合理的预成形设计.根据能量最小原理和最小阻力原理,利用塑性变形过程中坯料的流动规律与静电场等势线分布类似这一特性,提出一种能够进行预成形设计的新方法--类等势场法,并采用该方法对粉末高温合金盘件进行预成形设计,从中优选出6组预成形形状,并利用商用有限元软件MSC/SuperForm对上述预制坯的等温成形过程进行数值模拟,得到了6组粉末高温合金盘件终锻结束时各个部分的等效应变分布以及预锻和终锻的变形程度分配.通过对盘件轮毂、辐板和轮缘三部位以及整体盘件最大等效应变和最小等效应变的比较与分析,以及预锻变形量和终锻变形量的比较,并参考模具法向和切向的受载情况,认为选择3号预锻模为最佳方案.结果表明,该方法克服了传统方法精度低、耗时和耗力等缺点,其结果可靠. 相似文献
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Clarence W.DE SILVA 《Instrumentation》2019,(4):72-84
An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t... 相似文献
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INTEGRAL EQUATION METHOD'S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES 总被引:1,自引:0,他引:1
LI Cheng ZHENG Yanping 《机械工程学报(英文版)》2008,21(6):115-118
The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value. 相似文献
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30 keV Ga+ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z2, and shows a non-monotonic relationship between contrast and Z2. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z2, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory. 相似文献
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This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an... 相似文献
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分布动态载荷识别的抗噪处理 总被引:2,自引:2,他引:0
针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性. 相似文献
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针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。 相似文献
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The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar... 相似文献
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The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods.... 相似文献
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J. A. Williams 《Lubrication Science》1997,3(3):267-306
Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface. 相似文献
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CHEN Sunyi 《机械工程学报(英文版)》2007,20(6):13-17
A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion. 相似文献