基于遗传算法的超硬磨料高速砂轮基体截面优化设计

基于遗传算法,采用有限元分析软件ANSYS对砂轮基体截面进行优化设计.首先对已有超高速砂轮进行了有限元分析,然后采用ANSYS提供的参数化设计语言(APDL)建立超高速砂轮基体的参数化模型,并与遗传算法相结合,以砂轮基体最大最小环向应力差最小化为目标函数进行优化.结果表明:与现用超高速砂轮相比,优化设计后的砂轮基体的环向应力分布均匀,砂轮基体的最大环向应力以及膨胀量明显减小.     

高速／超高速砂轮基盘的优化分析

为了确保高速/超高速砂轮的安全性,对砂轮的受力进行了系统分析.认为砂轮工作时,砂轮的安全性主要受离心力的影响,整体式高速砂轮应以校核砂轮的抗拉强度为主,而超高速分体式砂轮应以控制基盘的径向膨胀量为主.并以ANSYS软件为辅助工具,分别对砂轮基盘的形状、材料、孔径比进行了分析和选择.最后,以最小径向膨胀量为目标函数,在200m/s的转速下,对钛合金梯形基盘的截形进行了最优化.     

高速超高速磨削用CFRP砂轮基体优化设计

介绍了高速超高速磨削用碳纤维增强复合材料CFRP (carbon fiber-reinforced polymer)基体砂轮的分析和设计。以降低磨削功率消耗,提高砂轮安全性能为主要目的,有限元分析比较了不同基体材料、截面形状及铺层方式对砂轮性能的影响,揭示了CFRP砂轮的性能优势。从砂轮气动特性和动态特性入手,优化设计了砂轮基体截面。并完成1种超高速磨削用CFRP砂轮基体设计。     

基于成形磨削的渐开线螺旋齿轮研究

以解析几何与齿轮啮合原理为理论基础,分析砂轮成形磨削渐开螺旋面工件时二者的相对位置关系,建立砂轮成形磨削数学模型,推导出砂轮回转面与工件螺旋面的接触条件及砂轮轴向截形方程,分析研究接触线与砂轮截形性质。结合实例,运用MATLAB计算出砂轮的轴向截形坐标,使用UG建立齿轮与砂轮三维装配模型。为验证砂轮截形数据的正确性,对螺旋齿轮进行磨削试验,试验表明对于成形磨削参数计算还需继续优化完善。     

高速砂轮基体应力分布的有限元分析

计算和分析高速旋转圆盘应力的分布情况,给出了理论的计算公式。以高速砂轮基体为例。进行有限元数值模拟,给出了砂轮基体在高速旋转时的应力分布结果。计算分析了不同的砂轮速度和不同的结构参数对高速砂轮基体的最大拉应力的变化情况,为高速砂轮的结构设计和优化提供有益的参考。     

大型超硬材料砂轮基体的数字化仿真设计

在本文涉及的大型高速超硬材料砂轮钢基体的设计过程中,利用三维软件Pro/e及仿真分析软件ANSYS对设计过程进行了数字化的仿真分析。在对砂轮基体进行参数化建模和优化设计后,对砂轮基体进行强度和动态特性分析,并联合三维软件完成了砂轮基体的数字化建模。通过优化设计分析和数字化模型,得到了砂轮基体的质量属性和工作过程中基体内部的应力、应变以及变形位移量的直观图形。以分析结果作为参考,以期为大型砂轮基体的设计制造提供相应的理论依据。     

超高速陶瓷结合剂CBN砂轮制造及应用

介绍了超高速陶瓷结合剂CBN砂轮的制造技术,从基体设计、CBN磨料选择、陶瓷结合剂制备、砂轮配方及尺寸的确定、砂轮制备等方面进行了详细分析。最后对超高速陶瓷CBN砂轮的应用前景进行了展望。     

CBN砂轮超高速磨削条件下加工表面粗糙度的实验研究

在高速超高速磨削工艺实验基础上,分析了砂轮线速度、切削深度、最大未变形切屑厚度等工艺参数对45#钢、40Cr两种材料磨削表面粗糙度的影响,揭示了在高速超高速磨削条件下用CBN砂轮进行磨削时,表面粗糙度值随砂轮线速度的提高而减小,随切削深度及最大未变形切屑厚度增加而加大的变化规律和机理。为特定材料在高速超高速磨削条件下的加工提供了参考依据。     

大导程滚珠丝杠副螺母的截形计算与加工仿真

根据螺旋面加工原理、齿形啮合原理及回转面砂轮加工螺母工艺建立了相应的数学模型,并推导出砂轮截形的计算公式;采用数值计算方法求解砂轮截形参数,进一步得到修整器靠模板的参数;在此基础上,利用Pro/E软件对大导程滚珠丝杠螺母、砂轮和砂轮修整器进行了实体建模,并对砂轮的修整过程和螺母的加工过程进行了运动仿真,有效地验证了砂轮截形的计算结果。     

四圆弧齿轮成形磨削砂轮截形的设计计算

四圆弧齿轮成形磨削的关键之一就是求解成形砂轮的轴向截形。根据成形法磨削原理建立坐标系,通过四圆弧齿轮齿面方程和齿轮齿面与成形砂轮磨削表面的接触条件,运用空间坐标转换求得最终的砂轮轴向截形。最后,借助MATLAB对所求的砂轮轴截面截形进行了计算仿真,并通过加工试验对求得的砂轮截形进行了验证。     

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.     

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。     

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....     

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.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.