高速精密冲床可靠性增长试验与分析

针对某新型高速精密冲床可靠性水平不高的问题,进行了可靠性增长试验研究。设计了可靠性增长试验的试验剖面和试验计划;选取了AMSAA模型作为试验的增长模型;为能及时发现与定位故障,并给故障分析提供依据,搭建了高速冲床可靠性试验平台;在此基础上进行了可靠性增长试验。根据试验平台提供的机床性能信息,对试验中出现的故障问题进行了分析,然后制定并实施了改进措施;最后,进行了可靠性增长分析。结果表明试验过程中该型高速精密冲床可靠性有明显增长趋势,试验结束时,机床平均故障间隔时间MTBF(mean time between failure)的估计值达到了试验目标值。     

高速冲压机床可靠性评价系统开发及应用

分析了当前常用的可靠性评价指标,根据高速冲压机床的特点,建立了可靠性评价系统,对其进行了总体设计,分析了系统需求、功能模块及可靠性评价流程。基于Matlab平台对高速冲压机床可靠性评价系统进行了系统开发。根据记录的高速冲压机床的故障数据,采用建立的可靠性评价系统,进行了可靠性指标的计算。基于高速冲压机床动态精度可靠性试验,进行了性能退化分析。     

通用机床主传动系统CAD的研究

基于VB6.0研究、开发出通用机床主传动系统CAD，实现了利用计算机对机床主传动系统的设计，对提高主传动系统的可靠性，促进相应产品质量的提高具有重要意义。     

机床主轴的可靠性及可靠性灵敏度分析

基于经典力学理论建立了主轴刚度的可靠性分析模型,并使用Monte Carlo方法进行了可靠性及可靠性灵敏度分析,研究了设计参数的改变对主轴刚度参数的可靠性的影响。为机床主传动系统的可靠性分析及优化设计提供了理论依据。     

高速冲床可靠性加速试验研究

通过分析高速冲床的维修数据,找出影响其可靠性的主要故障模式,发现高速冲床的主要故障模式是油、气部件损坏、零部件损坏和油、气渗漏。通过故障可测性和失效机理加速性分析,选定冲压载荷和冲压速度作为可靠性加速试验的加速应力,并确定了高速冲床可靠性加速试验的试验内容和监控项目,以此为基础设计高速冲床的可靠性加速试验方案,最终为高速冲床的可靠性增长奠定基础。     

加工中心主轴可靠性试验装置设计与应用

针对加工中心的关键部件主轴,对其可靠性试验的必要性进行了阐述,提出了一种快速加载的可靠性试验方法,并根据主轴的结构特点和可靠性试验的具体要求,实现了主轴可靠性试验装置的方案设计和详细设计。通过主轴可靠性试验装置的搭建,开展了主轴可靠性的相关加载试验,并将该试验结果与加工中心其他可靠性试验相结合,通过相应的数据分析软件,评定出机床的薄弱环节和可靠性量化指标。以便从设计、制造、使用和维护等各方面采取对策和措施指导主轴单元的可靠性设计,从而保证主轴设计和使用过程中的可靠性增长。     

摇臂钻床主传动系统最大扭矩的测定

摇臂钻床“主传动系统最大扭矩”这一技术参数,在我国有关专业标准和产品技术文件中都有明确的规定。它不仅是机床设计计算的主要依据之一,也是用户合理使用机床的主要依据之一。在部标准JB2278-78《金属切削机床通用技术条件》第67条“机床的负荷试验”第(2)款中,对“机床主传动系统最大扭矩的试验”作了明确规定。作为一项考核机床工作能力和机床质量的重要指标,机床制造厂在摇臂钻床的制造与验收过程中,都按上述部标准的规定进行摇臂钻床主传动系统最大扭矩的试验。 对于主传动系统最大妞矩的试验,部标准规定可用仪器代替切削试验,但应…     

基于振声实验的车床动态性能研究

对CA6140型车床进行了空运转试验和噪声试验,获取机床的空运转状况下的振动和噪声信息,分析研究了机床的动态性能,尤其是机床的抗振性能做出了评价,并用振动诊断和噪声诊断方法,找出了该车床主轴箱传动系统中的薄弱环节,并提出相应的改进措施,以期进一步提高其抗振性。     

基于Top-Down的主轴箱传动系统设计

主轴箱是组合机床中的专用部件,其传动系统的设计是决定组合机床设计效率的关键。利用Pro/E建立主轴箱各传动零件的三维参数化模型,并对主轴箱传动系统进行Top-Down的参数化布局设计,实现主轴箱传动系统的自动装配,从而达到快速设计主轴箱传动系统、缩短产品设计周期的目的。     

按钮型主令电器寿命试验仪的设计与研究

设计了一种按钮型主令电器寿命可靠性实验专用试验仪.设计采用了先进的基于.NET平台的SCADA自动化监控系统和PLC程序控制系统,实现了对各种型号按钮型主令电器在不同的试验类型、不同的试验应力条件下的寿命可靠性试验.试验杈技术先进,精度高,满足国标要求,为按钮型主令电器的性能检测和质量控制提供了先进的检测手段.     

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.