卧式螺旋卸料沉降离心机转鼓的有限元仿真

应用VisualNastran有限元仿真软件对转鼓在各种载荷工况下的应力应变进行了仿真分析，并调整转鼓壁厚参数来研究参数的变化对转鼓的强度和径向变形的影响。仿真结果表明：转鼓的最大应力位于靠近大端鼓底的柱形筒体的内壁上；物料离心液压引起的最大应力和最大径向位移随着转鼓壁厚的减小而增大；转鼓自身质量离心力在壁内产生的最大应力和最大径向位移与鼓壁厚度无关。     

转鼓局部结构对其强度影响的研究

针对现行离心机转鼓设计方法因对转鼓局部结构的设计关注甚少,从而影响了转鼓经济性和安全性的问题,以用现行转鼓设计方法设计的转鼓基本结构为研究对象,利用COSMOSWorks软件对整体转鼓进行有限元应力分析的功能,就转鼓筒体与挡液扳的连接处、加强箍等局部结构对转鼓强度影响进行了分析研究,并根据局部结构与转鼓应力之间的关系得出了较为合理的结构.研究结果表明:该研究得出的转鼓局部的合理结构对离心机转鼓设计具有实用帮助;提出的在关注转鼓的整体结构设计的同时更应关注转鼓的局部结构设计的新观点.对扭转转鼓设计和制造的现行做法也具有现实的指导意义.     

卧式螺旋卸料过滤离心机转鼓开孔削弱系数的研究

开孔转鼓是卧螺离心机的主要部件,转鼓开孔后强度会削弱,因此,对于转鼓开孔削弱系数的分析研究是十分必要的。利用有限元分析软件ANSYS10.0对开孔转鼓进行参数化建模、网格划分、施加对称约束,然后进行强度应力分析,研究开孔转鼓强度应力的变化规律,转鼓开孔处会产生应力集中,最大应力也出现在开孔的位置。通过节点应力对比的方法,研究转鼓开孔后强度应力变化规律,获得产生的最大强度应力的数值和节点M的坐标,在未开孔转鼓体上找到与节点M坐标相同或者最接近位置点的Stress intensity值,通过对比方法获得转鼓开孔削弱系数。     

碟式分离机转鼓强度的有限元分析与实验验证

讨论了轴对称有限元法在DBY—50碟式分离机转鼓零件应力分析与强度设计中的应用。对DBY—50分离机转鼓的顶盖、活塞、主锁环、本体及滑块等五个零件,进行了应力计算,得到这些零件的应力状态的大量信息。文中给出了有关零件的应力分布曲线和等应力曲线,讨论了它们的结构强度,并提出改进结构设计的意见,文中还对有限元计算结果作了实验验证。     

卧式螺旋离心机关键结构的静力学性能分析与优化

为提高卧式螺旋离心机的性能,采用有限元分析的方式对柱-锥形转鼓的强度性能进行分析,并在此基础上,对转鼓的关键参数长径比及壁厚进行优化分析,实现了对转鼓结构的改进,提高了离心机使用性能,提高了煤炭分选效果.     

虹吸式离心机转鼓结构的有限元应力分析

利用ANSYS有限元软件建立了虹吸离心机转鼓的二维有限元模型,对其在正常工作状态下的整体结构进行了应力分析,得到了转鼓的径向、轴向变形和应力分布,以及最大应力点,并对局部应力进行了进一步的分析.结果表明原设计的虹吸式离心机转鼓的强度和刚度均满足要求,但是在拦液板和转鼓底边缘的设计过于保守,因此在保证强度和刚度的前提条件下,减少了其边缘连接处的厚度.     

上悬式离心机转鼓的动态性能分析与优化

为了解决上悬式离心机运行中跨越临界转速出现共振、冲击等问题,文中运用有限元分析法对上悬式离心机转鼓进行了动态分析,探讨了转鼓各个结构参数对动态性能的影响关系,并以此为基础对转鼓系统动态性能进行了优化,分析获得了转鼓各结构对动态性能的影响程度.优化后转鼓临界转速避开了工作转速,分离性能提高了16%.所得转鼓各参数对动态性能的影响关系,为转鼓系统的进一步改进奠定基础.     

基于Workbench的碟式分离机转鼓应力等效线性化分析

根据压力容器分析设计标准和分类准则,结合碟式分离机转鼓应力分布特点,对碟式分离机转鼓的应力分类和强度评定问题进行讨论。本文简略介绍了应力等效线性化的基本原理以及应力分类线选择等问题。通过Workbench有限元分析软件对碟式分离机转鼓进行应力等效线性化分析,对各条路径上分离出来一次总体薄膜应力、一次弯曲应力和一次薄膜应力+一次弯曲应力按照对应的失效准则进行校核,得出碟式分离机转鼓在正常工况下运行是安全可靠的。计算得出的转鼓各部件最小安全系数为结构进一步优化提供了理论依据。     

GD-1300上悬式离心机转鼓的应力分析与优化

运用有限元分析软件ANSYS对上悬式离心机关键部件-转鼓在正常工作状态下进行了分析,找出了该转鼓的危险点所在位置,对转鼓的结构进行了改进;并运用有限元分析软件对改进后的转鼓进行校核.结果表明改进后的结构满足强度和刚度要求.将CAD和ANSYS软件进行联合的方法能够发挥各软件的优势,缩短研发周期,得到精确结果.     

基于有限元的锁环静态分析与结构优化

以碟式分离机为研究对象,针对转鼓锁环的结构特点与受力特性,建立转鼓锁环的实体模型与有限元模型,通过有限元仿真软件对锁环结构在静载作用下进行应力分析,依据分析结果,对锁环几何结构进行了多目标优化设计,既满足强度要求,又减轻了锁环质量。     

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...     

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。     

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.     

Fractional order nonsingular terminal sliding mode control for flexible spacecraft attitude tracking

This paper investigates a fractional terminal sliding mode control for flexible spacecraft attitude tracking in the presence of inertia uncertainties and extern...     

奥氏体不锈钢表面双辉等离子渗锆的动力学

利用双辉等离子渗金属技术在0Cr18Ni9Ti奥氏体不锈钢表面制备了一层均匀、致密、呈良好冶金结合的渗锆合金层,并对1 060℃下的渗锆动力学进行了研究。结果表明:随着距锆合金层表面距离的增加,锆元素的含量呈梯度递减,扩散系数逐渐减小,而扩散激活能逐步增大;在1 060℃采用双辉等离子技术渗锆时,渗锆合金层表层的空位密度为2.945×(1012~1013)cm-2,与相同温度下采用常规渗金属工艺相比,提高了1~2个数量级。     

气化炉三维扫描测量与数据处理

以德士古气化炉耐火砖的内壁蚀损检测设备为基础,对采集到的点云数据做了进一步处理.通过对数据的筛选和剔除,实现了数据点的平滑降噪细化和精简.然后利用点云对整、网格划分和分色显示等方法,最终完成了内壁腐蚀情况的三维建模.重点讨论了点云数据的预处理及后处理的方法,并根据内壁耐火砖的腐蚀阈值,提出了一种气化炉内壁腐蚀区域的识别与分割方法.对耐火砖的腐蚀分析、气化炉的生产与维修提供了可靠依据,并在工程应用中获得了一致认可.