一种新型矿用液压挖掘机履带张紧系统的设计

该文综述了一种新型矿用液压挖掘机履带张紧系统.履带张紧系统是履带式行走机构的一个重要组成部分,它的性能好坏对履带式液压挖掘机的行驶性能有很大影响.该文通过分析矿用液压挖掘机的行走工况和履带及张紧缸的受力情况,并对比了各种履带张紧系统的优缺点,设计了一种新型矿用液压挖掘机的履带张紧系统.通过仿真,该履带张紧系统能够在不同路面状况下对履带进行实时张紧,实时监测,使液压挖掘机安全可靠的行走.     

大型矿用挖掘机联合仿真应用研究

研究针对大型矿用挖掘机的机械结构和变频控制系统的组成和特点;在AMESim平台下,建立了包括变频调速驱动系统和矿用挖掘机工作装置刚体模型的机-电联合仿真虚拟样机;对典型的推压-提升工况进行了仿真,并与文献中的测试数据进行对比,证明了机-电联合仿真对大型矿用挖掘机的研究分析具有重要价值。     

一种矿用液压挖掘机能量再生控制系统设计及仿真分析

该文综述了一种矿用液压挖掘机能量再生控制系统。工作装置是液压挖掘机的重要部件。在矿用液压挖掘机挖掘过程中,动臂油缸缩回,可控制整个工作装置下放,同时,工作装置自重会对动臂油缸产生冲击能量;通过分析以上工况,为了充分利用工作装置下放时自重产生的能量,进行能量再生利用,减少原动机能量输出,特计算和选择了再生阀,设计了一种矿用液压挖掘机能量再生控制系统。而后通过ITI-Simulation X软件建模仿真分析,对该系统进行了验证。     

大型矿用液压挖掘机行走系统建模及仿真研究

大型液压挖掘机履带行驶系统的传统计算方法精度低、仿真计算的难度大,针对这种状况,提出了一种改进的仿真方法。该方法通过数据表将动力学软件仿真得到的力学参数导入到系统仿真软件SimulationX中进行液压系统仿真计算,对履带前进和后退两种基本工况下的动力学机构仿真结果和液压系统仿真结果进行分析。通过对仿真结果与理论计算结果的比较,证明该方法得到了较好的履带行走系统整体仿真计算精度和较快的仿真计算速度,为大型液压挖掘机履带行走系统的精确设计提供了一种较为实用的方法。     

基于AMESim分析的矿用钻机行走液压系统性能与能耗分析

设计一种矿用行走液压系统,并利用AMESim仿真模拟软件,对矿用钻机行走液系统进行了工作性能和能耗问题进行了分析。结果表明:行走液压系统在不同工况下均能保持较为稳定的工作性能,在直行工况下的能量利用率较高,但在转弯和爬坡工况下的能量利用率还有待进一步的改进和提升。     

液压挖掘机动臂结构优化设计

研究基于UG/ANSYS的液压挖掘机动臂结构优化设计方法.以斗山某中型液压挖掘机为研究对象,借助UG软件完成工作装置、回转装置和行走装置3部件参数化建模并装配.分析计算典型危险挖掘工况下动臂各铰点的受力,利用ANSYS软件进行静力学分析,针对薄弱部位及应力集中问题,优化动臂局部结构.仿真结果表明:在危险工况下,优化后动...     

大型矿用履带式挖掘机接地压力动力学研究

针对接地压力是衡量履带式机械性能的要素之一,结合大型矿用履带式挖掘机的行走机构,利用动力学分析软件ADAMS,基于极限坡路及极限转向2种典型作业工况的动态特性进行了动力学仿真研究.通过定量及定性的分析,得到了不易于进行物理实验的大型机械设备的行走装置接地压力分布规律,所得结论为该类行走机构载荷分布的深度分析及性能研究提供了基础.     

WYD390液压挖掘机工作装置运动学及动力学分析

由于液压挖掘机具有结构紧凑、操作方便、运动灵活及易于维护保养等优点,大型矿用液压挖掘机在国外已经得到了很广泛的应用.现对太原重工研发设计的国内首台400t级矿用液压挖掘机的工作装置进行了运动学和动力学分析,为本产品工作装置的优化设计及今后的相关产品的研发提供了理论参考.     

基于ADAMS的仿真技术在履带行走装置的应用

通过对ADAMS软件的简介,对其特点及功能有了一定的了解之后将现有模型导入软件中施加约束,并用宏命令施加接触力。最后利用ADAMS软件对矿用挖掘机履带行走装置进行动力学仿真分析,从仿真曲线中得出了一些规律,从而为其他大型机械的履带行走装置的动力学仿真研究提供了有价值的依据。     

大型液压挖掘机斗杆挖掘阻力的离散元素法研究

针对由于缺乏铲斗挖掘阻力等关键数据而导致在大型正铲液压挖掘机工作装置、液压系统设计时只能采用类比法而造成整机性能差的问题,对挖掘机斗杆挖掘阻力进行了离散元研究,提出了一套仿真评估方法:运用离散元素法,在EDEM中建立了矿堆模型,通过选择Hertz-Mindlin无滑动接触模型计算了元素间接触力,模拟了大型正铲液压挖掘机斗杆挖掘工况,分析研究了挖掘过程中铲斗所受挖掘阻力。将EDEM中所得挖掘阻力加载到ADAMS挖掘机动力学模型,进行工作装置和液压回路参数校核以及挖掘阻力实验验证。研究结果表明,挖掘阻力的仿真与计算为大型液压挖掘机工作装置和液压系统设计提供了可靠依据。     

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.