HSK-E40刀柄与机床主轴联结系统的变形分析

在对HSK-E40刀柄与机床主轴接触状况深入分析的基础上,采用有限元方法对HSK-E40刀柄和机床主轴联结系统在不同转速下的膨胀变形量进行分析模拟。分析表明,随着机床主轴转速的提高,主轴/刀柄联结系统的膨胀间隙将增大。适当提高轴向预紧力和联结面间的过盈量可以有效地改善联结性能和提高加工精度。为增加联结的可靠性,HSK-E40联结系统的过盈量应为15~20μm。     

高速主轴系统非线性动力学建模与数值仿真

为了深入分析主轴-刀柄系统的非线性动力学特性,以高速切削机床的主轴-刀柄系统为研究对象,综合考虑主轴-刀柄结合面及角接触球轴承非线性接触力,基于铁木辛柯梁理论建立了包含转动惯量、剪切变形及偏心质量影响的主轴-刀柄系统有限元动力学模型。对该模型进行数值计算的结果表明,由于主轴-刀柄结合面及支承轴承处非线性接触力的存在,主轴-刀柄振动系统具有非常复杂的周期运动、倍周期运动和混沌运动,倍周期分岔是主轴-刀柄系统通向混沌的主要道路。系统在某些偏心量下经历几次倍周期分岔最终会产生混沌运动,应在实际设计过程中尽量避开该参数区域。     

HSK-E40刀柄与机床主轴联结系统的变形分析

在对HSK-E40刀柄与机床主轴接触状况分析的基础上,采用有限元方法对HSK-E40刀柄和机床主轴联结系统在不同转速下的膨胀变形量进行模拟分析.分析表明,随着机床主轴转速的提高,主轴/刀柄联结系统的膨胀间隙将增大.适当提高轴向预紧力和联结面间的过盈量可以有效地改善联结性能和提高加工精度.为增加联结的可靠性,HSK-E40联结系统的过盈量应为15～20 μm.     

高速主轴/刀柄联结的可靠性分析

高速主轴/刀柄的联结性能对加工精度和机床可靠性具有重要影响。采用机械零件可靠性设计的方法,对高速主轴/刀柄联结的可靠性进行了分析,建立了高速主轴/刀柄联结强度和传递扭矩的可靠性模型,并给出了可靠度的通用计算公式,利用ANSYS有限元分析软件,计算出不同转速、过盈量、夹紧力作用下的高速主轴/刀柄联结的接触应力,系统地揭示出不同夹紧力作用下,过盈量、转速对高速主轴/刀柄联结强度和传递扭矩的可靠性的影响,研究结果为实际使用过程中夹紧力、过盈量、转速大小的选用提供了参考。     

高速加工用KM刀柄/主轴的联结特性及数值模拟

本研究以KM4030刀柄为研究对象,通过改变过盈量、夹紧力,利用非线性有限元方法系统研究了不同参数对刀柄/主轴联性能的影响。借助有限元软件ANSYS,深入揭示了夹紧力、过盈量对KM刀柄/主轴联结系统的径向变形、接触应力及接触间隙的影响,为高速加工用新型刀柄及其工具系统的开发提供一定的理论依据和技术支撑。     

考虑主轴—刀柄—刀具结合面的高速主轴系统动力学特性有限元建模

高速主轴系统主轴—刀柄—刀具结合面动力学性能是影响主轴切削效率、加工质量以及加工性能的重要因素之一,而结合面的建模又是研究主轴系统动力学特性的基础。将主轴—刀柄—刀具结合面简化为分布弹簧,并基于并联转子的建模思想,采用有限元法完成了主轴系统的有限元建模。在明确分布弹簧的布置方式以及弹簧刚度的确定方法的基础上,提出考虑主轴—刀柄—刀具结合面的高速主轴系统动力学特性有限元建模流程。以安装BT系列刀柄的某立式加工中心主轴系统为例,利用所提出的方法进行有限元建模并求解刀尖点的频响函数,与实际测试的对比说明,该建模方法能够更好地模拟该主轴系统的动力学特性。     

基于结合部的HSK主轴-刀柄系统动态特性分析

建立了HSK主轴-刀柄结合部的有限元模型(FEM),利用弹性理论和黏性阻尼理论辨识结合部内各位置的刚度和阻尼参数。提出将HSK主轴-刀柄系统分为HSK主轴、主轴-刀柄结合部和刀柄三部分:HSK主轴与刀柄简化为多段Timoshenko梁,并使用响应耦合法来计算其频响函数;主轴-刀柄结合部简化为多点弹簧-阻尼模型,采用多点响应耦合法来计算其频响函数;将各个部件的频响函数进行刚性耦合,进而获得基于结合部的HSK主轴-刀柄系统频响函数。分别假定HSK主轴-刀柄结合部为刚性连接、5点弹性连接和7点弹性连接,计算其频响函数,并与实验结果相比较得到相应的结论。     

高转速下主轴-双面锁紧刀柄接触特性预估

采用有限元方法获得不同转速下端面和锥面的接触压强,基于该压强采用三维分形和赫兹接触理论计算双面锁紧刀柄与主轴的接触刚度,建立高转速下主轴-双面锁紧刀柄系统仿真模型。分析不同参数对主轴-双面锁紧刀柄(BTF40)系统锥面接触率及结合部接触刚度的影响规律,确定了该新型刀柄的极限转速、拉刀力、碟簧刚度和碟簧预紧力的合理取值区间,研究结果为双面锁紧刀柄的设计与优化提供了理论依据。     

基于RCSA的刀尖频响函数预测方法

为快速获取构建铣床稳定性叶瓣图所需的主轴—刀柄—刀具系统频响函数,提出一种有限元和响应耦合子结构分析法(RCSA)相结合的预测方法。以某型号主轴系统为研究对象,利用有限元法分别计算主轴、刀柄、刀具端点频响函数,再使用RCSA分别耦合主轴—刀柄结合面、刀柄—刀具结合面,最终得到主轴—刀柄—刀具系统刀尖频响函数。将得到的频响函数与理论算法以及完全有限元方法对比,在5000Hz以内,前7阶模态最大误差不超过15%。该方法可以在机床更换刀柄或刀具时只计算对应部分的频响函数,从而实现主轴—刀柄—刀具系统刀尖频响函数的快速预测。     

HSK主轴—刀柄结合部参数辨识及影响因素分析

HSK主轴—刀柄结合部简化为并联均布的弹簧—阻尼模型,根据HSK主轴—刀柄系统的结构,在ANSYS软件中构建HSK主轴—刀柄结合部的有限元模型。基于有限元分析结果,使用弹性理论辨识HSK主轴—刀柄结合部内各位置的刚度参数;采用粘性阻尼理论辨识HSK主轴—刀柄结合部内各位置的阻尼参数。确定影响HSK主轴—刀柄结合部参数的主要因素为过盈量和拉紧力,分别探究过盈量和拉紧力对HSK主轴—刀柄结合部参数的影响规律。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

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...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

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.     

Non-monotonic material contrast in scanning ion and scanning electron images

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.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

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....     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

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...     

分布动态载荷识别的抗噪处理

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.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

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。     

The laboratory simulation of abrasive wear

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.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

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.