基于油管柔性体的上卸扣仿真模型与分析

油管上卸扣过程中油管与油管钳相互作用力学行为是十分复杂,由于油管钳头与油管壁接触状态的物理试验很难模拟,文章以油管钳卡紧部件的刚体运动学和动力学模型,油管柔性体力学模型为基础,建立起油管钳-油管上卸扣系统刚柔耦舍仿真模型。通过对模型的仿真试验,找到油管钳上扣的临界咬入深度,既能保证油管与油管钳之间无相对滑动,又能保证油管钳咬入深度最小。通过咬入深度与接触力的关系曲线找到此时钳牙对油管的临界接触力,为以后研究和设计油管钳提供理论基础和数据参考。     

石油套管钳钳头夹紧机构的仿真分析与试验研究

钳头夹紧机构是石油套管钳的重要组成部分,直接关系到套管钳能否安全可靠工作。应用Workbench软件对所设计的套管钳钳头夹紧机构的三维模型进行了力学分析,分析了钳头各组成部分的应力情况,并首次采用先进的压力胶片测量方法进行了钳头夹紧机构的应力测试分析,验证了设计和仿真分析的正确性,为套管钳钳头结构的优化设计提供了可靠依据。     

在旋紧时套管钳的颚板结构分析与优化

为了保障下套管作业的安全和可靠性,根据套管钳关键部位颚板的受力特点和结构特征,可知在旋紧时套管钳的颚板受力最大。根据颚板的结构特点进行模型简化,推导出理论计算公式并计算出理论最大应力,经过ANSYS有限元分析和理论计算结果互相验证。最后运用有限元软件ANSYS对颚板的滚轮孔加圆角和颚板背部加肋板的结构进行结构分析,分析结果表明:改进后颚板最大应力减少了3.5%,最大变形降低了6.4%,其结果对推进套管钳的改进和优化提供了一定的参考。     

间隙密封液压缸的活塞卡紧力分析

该文以某间隙密封式液压缸为研究对象,运用CFD方法,借助FLUENT软件对偏心状态下三种不同平衡槽活塞进行卡紧力分析。仿真结果表明:开矩形槽时,活塞的液压卡紧力最小。     

基于虚拟样机技术的变胞机构构态变换研究

变胞机构的构态变换是变胞机构研究的重要内容,由于机构构态的突然改变,变胞机构在这个时刻会发生冲击.冲击对变胞机构的影响是变胞机构研究的一个难题,以一个平面五杆变胞机构为例,通过虚拟样机技术对变胞机构的变胞过程进行动力学仿真,从而得到机构发生冲击振动时刻的运动曲线,并分析了不同驱动条件下冲击对机构的影响.仿真结果表明,改...     

棉纺精梳机钳板驱动机构动力学及有限元分析

为研究精梳机速度对钳板驱动机构各机件受力的影响及不同速度时钳板驱动机构各机件的选材方案,利用ADAMS软件得出了不同速度时一个工作周期内钳板驱动机构各机件的最大受力;利用Ansys有限元分析软件对钳板驱动机构各机件应力分布进行有限元仿真。结果表明：钳板驱动机构各机件连接副在一个工作周期内滑套与曲轴铰接处受力最大,滑套与滑杆处次之;钳板驱动机构各机件连接副的最大受力随着精梳机速度的增加而迅速增大,当精梳机的速度由500钳次/分钟增大到700钳次/分钟时,滑套与曲轴铰接处的最大受力增加了92.73%。从钳板驱动机构运行的安全性及选材的经济性两方面考虑,得出了精梳机速度分别为500、600及700钳次/分钟时各机件最合适的选材方案。     

基于ADAMS和MATLAB的翻转机构联合仿真研究

建立三自由度翻转机构模型,将模型导入ADAMS中添加约束和驱动,进行运动学仿真,输出气缸回转轴和翻转板回转轴的角度变化曲线。建立翻转机构ADAMS动力学模型,创建活塞杆上端轨迹与输入输出变量,导入MATLAB/SIMULINK模块。在SIMULINK中建立控制系统,以气缸移动速度为输入指令,调整控制参数,实现活塞杆末端的既定轨迹跟踪,输出不同位置增益的响应曲线。仿真过程通过改变控制系统的参数,发现增大P可增加系统的响应速度,增大X_p可消除超调现象,减少振荡。联合仿真的研究为实际数控系统的机电耦合提供了设计依据。     

基于ADAMS的汽车起重机变幅机构优化设计

以QY20汽车起重机为研究对象,利用ADAMS软件建立其变幅机构的虚拟样机,并对变幅机构的工作过程进行仿真,获得了变幅油缸中变幅力随时间变化的曲线.据此,以变幅过程中变幅油缸负载力波动值最小为目标,对变幅机构三铰点位置进行了优化.结果表明,优化后的铰点位置改善了变幅油缸活塞杆与吊臂相连铰点的受力状况,减少了对变幅液压系统的压力冲击.通过仿真试验发现,变幅机构单目标优化存在一定的局限性.     

基于RecurDyn的八连杆机构参数化设计及优化

以大吨位冲压压力机中的闭式八连杆机构为研究对象,根据滑块总行程、最大拉伸深度、有效拉伸过程中的最大拉伸速度等3项要求,对其进行杆系尺寸优化设计.在RecurDyn平台上建立了八连杆机构的参数化模型,经过运动学仿真,获得滑块的位移和速度曲线.基于位移曲线获得滑块总行程,基于速度曲线及有效拉伸过程中的最大拉伸速度要求获得可...     

基于AMESIM 的多孔形缓冲套的仿真与研究

基于缓冲套一般工作原理,提出一种多孔缓冲套结构的设计.液压缸在运行过程中通过不断改变缓冲套总节流面积,使得速度平稳下降,从而起到缓冲作用.并建立了数学模型,用AMESIM软件对缓冲套在液压缸中的应用进行了仿真,得出了缓冲腔的压力曲线,活塞的位移和速度曲线,通过设置不同的管道模型直径,对其参数进行了优化设计,仿真结果证明了这种缓冲套的缓冲效果好和实用性强.该缓冲套可以根据实际工况需要改变节流孔的大小位置和个数,实行对缓冲套装置的多样化设计,以保证生产实际的需要.     

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.     

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.