压力容器-管路-安全阀系统变保真度仿真模型研究

针对能源工业领域中常见的压力容器-管路-安全阀系统(以下简称:压力系统)开展了系统级变保真度模型的研究。从提高模型的仿真效率同时保证计算精度的角度出发,分别基于等效压力点方法、特征线理论和CFD技术对压力系统中的压力容器、连接管路和安全阀进行了元件级模型的构建和系统级模型的耦合。为了验证提出的建模方法的准确性,结合已有的实验结果进行了模型的精度验证,结果表明,构建的系统级变保真度模型具有较好的压力系统动态特性仿真能力,能够对压力容器和管路内的压力波动以及弹簧式安全阀的动态响应进行准确的计算。     

导引头稳定平台弹性干扰力矩分析与优化技术

为降低导引头稳定平台运动过程中,与其相连接的线缆和管路随之运动产生的弹性干扰力矩,以弹性细杆非线性力学理论为基础,对稳定平台所属的运动线缆和管路进行建模与仿真分析。在仿真分析的基础上,提出弹性干扰力矩的精确计算方法,并将其应用于线缆虚拟布线设计中。以弹性干扰力矩的仿真计算结果为判据,对线缆布局设计进行优化。通过实验验证,表明该方法可以有效地将弹性干扰力矩限制在允许的范围内,进而提高制导精度。     

基于Fluent流场数值仿真的管路流量计算

利用Fluent三维单精度求解器,对管路内的三维稳态流场进行仿真,利用后处理工具得到管路体积流量,并将Fluent数值仿真计算的体积流量结果与实测结果进行对比,数值仿真计算结果得到实际测量实验的验证。     

基于PLC控制的管路接头自动对接夹持器设计

为了提高现代空调制造企业中管路快速接头对接的自动化程度,实现机器换人的过程,分析管路快速接头的机械结构和工作原理,采用仿人手操作的对接方法,设计出一种基于PLC控制的五自由度气动夹持器。在分析气动夹持器的工作原理和控制要求的基础上,设计了对应夹持器的气压传动系统。介绍了三菱FX3U-40MT PLC与外部各元器件的连接,以及对PLC电气控制系统程序进行设计。在FluidSIM虚拟仿真实验平台上进行了电气控制下的气压回路仿真实验,验证了夹持器可以按照预定的动作实现管路快速接头的对接。     

基于立方插值拟质点法(CIP)的气动控制管路压力响应时间研究

气压制动系统的性能保证了车辆行车安全和制动稳定,气动控制管路作为控制部分是影响其压力响应时间的重要因素,精确分析和计算气动控制管路的压力响应时间具有重要意义。应用立方插值拟质点法（CIP）,求解得到了具有三阶精度的气动控制管路数学模型,并将仿真结果和实验进行对比,验证了仿真的准确性。应用灰色关联度定量分析了各参数对管路压力响应时间的影响程度,并基于响应面法进行了数值仿真实验,结果表明管长是影响压力响应时间最大的因素,同时压力响应时间的等高线图为气动控制管路的设计选型提供了理论参考。     

高真空环境下硅微机械陀螺品质因数的温度特性

分析了温度在高真空环境下对硅微机械陀螺品质因数的影响机理。阐述了热弹性阻尼的复频率模型和硅材料的温度特性,建立了品质因数温度特性理论模型,并对理论模型进行了仿真验证和实验验证。理论计算得到常温下品质因数的温度系数为-9.76×10-3/℃。利用ANSYS对品质因数的温度系数进行仿真分析,得到常温下品质因数温度系数的仿真值为-9.96×10-3/℃。对硅微机械陀螺进行品质因数温度实验,得到常温下品质因数的温度系数为-9.02×10-3/℃,与理论计算结果相差8.20%。实验结果表明:高真空环境下建立陀螺品质因数温度特性的理论模型可为陀螺的温度误差补偿提供理论依据,为陀螺的优化设计提供实际指导。     

模块式半挂车悬挂系统优化研究

在研究模块式半挂车悬挂技术的基础上,建立悬挂系统仿真模型分析其工作特点,针对悬挂系统管路泄漏问题提出在系统中加装防爆阀的优化方案.建立改进回路模型将仿真结果与原始回路进行比较,结果显示防爆阀可有效保护回路,并搭建实验平台验证了优化方案的正确性.     

基于精度和物性的虚拟装配技术

针对生产现场的需求和虚拟装配技术的发展趋势,提出了一种集精度、物理属性以及结构件与线缆管路仿真分析一体化的虚拟装配技术,从过程、精度和物理属性的角度实时地模拟装配现场和装配过程中可能出现的各种问题和现象,为实现产品的科学装配和装配质量预测提供r有效途径.给出了一体化的虚拟装配技术总体工作流程,并对虚拟环境下的装配精度预分析、基于物理属性的虚拟装配、线缆和管路布局与装配仿真等关键技术进行了阐述.通过仿真实验验证了该技术的有效性.     

外圆横向磨削力的仿真研究

磨削力的研究是磨削加工中的主要问题,在简化的单个磨粒的切削研究基础上,建立了外圆横向磨削的切向和法向磨削力的理论模型,通过Matlab6.5仿真,获得了磨削力仿真曲线,依据实验数据对经验常数进行修正,得到理想的仿真结果.通过与实验公式的对比验证,表明所建理论模型具有合理性与实用性.     

高强度钢大直径内螺纹的冷挤压加工

高强度钢大直径内螺纹冷挤压加工是一种新型的抗疲劳制造技术。本文介绍了３００Ｍ 内螺纹冷挤压成形特点,分析了冷挤压加工机理,并对冷挤压加工过程中扭矩变化规律进行了实验研究。     

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.