C／Cu复合材料自润滑轴承试验设计与设计准则的研究

根据均匀设计原理，对碳纤维铜基（简称C／Cu)复合材料润滑轴承的员试验参数予以科学排列，不仅使试验次数大大减少，而且使实验数据统计结果可靠，引入可靠性技术，建立了自润滑轴承在不同临界磨损效率下材料的可靠度－压强－速度曲线族及其计算方法，为碳纤维铜基复合材料自润滑轴承的设计提供了科学，可靠的依据。     

Ekonol/G/MoS2/PEEK复合材料的制备和正交试验研究

用正交试验设计方法和模压方法制备了Ekonol／G／MoS2／PEEK复合材料，通过方差和极差分析方法对材料的耐磨性能进行了研究，并用扫描电镜对磨损表面形貌进行了观察和分析。结果表明，用模压法制备此复合材料是可行的，复合材料具有优良的耐磨性能，其最优制备方案为A5B3C3D3E3；正交试验设计方法、方差和极差分析方法是行之有效的复合材料研究方法。     

复合材料构件可制备性设计方法研究

本文介绍了基于制造工艺可制备性的复合材料产品设计方法。依据并行工程原理,利用复合材料的制备工艺对构件的设计方案进行评价,从设计／制造系统一体化的角度来解决保证复合材料制造质量的问题。     

2D编织复合材料参数化分析和优化设计研究

基于C／SiC编织复合材料的微观结构形式,建立了包含不同尺度参数的C／SiC多尺度有限元分析模型;采用能量法预测了C／SiC复合材料的等效弹性常数,分析了不同参数对C／SiC力学性能的影响,从而建立了C／SiC复合材料多元多层微结构优化设计模型。计算结果表明,建立的有限元模型能有效地反应不同参数的影响,优化设计模型能有效地用于C/SiC复合材料为结构的设计。     

均匀设计法在聚醚醚酮复合材料摩擦学特性试验中的应用研究

采用均匀设计法设计了CF/SiO2/PTFE/PEEK复合材料,并模压成型;在摩擦磨损试验机上研究了PEEK复合材料的摩擦学特性,应用回归分析法对其摩擦学特性试验数据进行了分析,得到了摩擦学特性参数的回归公式。结果表明,均匀设计法应用于PEEK复合材料的摩擦学特性研究是可行的,能有效预测复合材料的摩擦学特性参数,回归分析结果与复合材料的摩擦磨损试验数据相吻合。     

均匀设计在碳—铜复合材料电阻率研究中的应用

均匀设计是一种新的试验设计方法,特别适用于多因素,多水平试验,能有效减少试验量,提高试验效率,在研究含粘结剂的碳－铜复合材料的电阻率时,采用均匀设计方法,给出了碳－铜复合材料导电性能随组分含量变化的经验公式。回归分析表明,粘结剂加入量对复合材料电阻率影响较大,碳－铜混合粉含铜量对复合材料电阻率的影响较小。根据回归归模型所建立的经验公式在试验所选配方范围内有很好的预见性,表明均匀设计是进行碳－铜复合材料电阻率多水平试验的良好方法。     

SiC粒径对铜基复合材料载流磨损性能的影响

采用粉末冶金法制备不同SiC粒径改性的SiC/C/Cu复合材料,研究SiC颗粒大小对材料组织结构和物理性能的影响;在载流摩擦磨损试验机上进行载流磨损试验,研究不同滑动速度下,SiC粒径对材料磨损率的影响。结果表明:在SiC/C/Cu复合材料中小颗粒SiC偏聚于C/Cu界面处,而大颗粒SiC均卡嵌在铜基体内,并且随着SiC颗粒的增大,复合材料硬度和密度稍有增加,孔隙率迅速降低,导电率增加;在较低滑动速度下,复合材料的磨损量随SiC粒径增大不断降低;在较高滑动速度下,随SiC粒径增大,复合材料的磨损率先降低后升高,25μmSiC改性的复合材料具有最低的磨损率。     

SiC粒径对铜基复合材料载流磨损性能影响

采用粉末冶金法制备不同SiC粒径改性的SiC/C/Cu复合材料,研究SiC颗粒大小对材料组织结构和物理性能的影响;在载流摩擦磨损试验机上进行载流磨损试验,研究不同滑动速度下,SiC粒径对材料磨损率的影响。结果表明：在SiC/C/Cu复合材料中小颗粒SiC偏聚于C/Cu界面处,而大颗粒SiC均卡嵌在铜基体内,并且随着SiC颗粒的增大,复合材料硬度和密度稍有增加,孔隙率迅速降低,导电率增加;在较低滑动速度下,复合材料的磨损量随SiC粒径增大不断降低;在较高滑动速度下,随SiC粒径增大,复合材料的磨损率先降低后升高,25 μm SiC改性的复合材料具有最低的磨损率。     

AlNp/Cu复合材料的热学性能

采用粉末冶金工艺制备了不同体积分数的AlNp／Cu系列复合材料,研究了复合材料从50-550℃的热膨胀行为,对不同体积分数的AlNp／Cu复合材料发生热变形的温度范围进行了分析计算,测定了AlNp／Cu复合材料塑性变形后的软化温度。结果表明：AlN的加入能够提高铜基体的软化温度且对铜基体的热膨胀起到明显的约束作用;在孔隙与热应力共同作用下,AlN颗粒含量达到一定程度时,AlNp／Cu复合材料膨胀曲线随温度的上升将产生非线性变化;加热过程中热应力造成的基体塑性变形使热循环后复合材料存在残余正应变。     

民用飞机复合材料设计许用值试验矩阵设计

试验矩阵是民用飞机复合材料设计许用值试验工作顺利推进的基础,为建立民用飞机复合材料设计许用值试验矩阵设计方法,对试验矩阵的各组成要素——试验项目、试验方法、试验数量、试验件铺层以及设计许用值影响因素分别进行了研究。试验项目取决于复合材料结构分析方法,给出了各试验项目对应的试验标准;提出的铺层选取原则适用于型号各阶段的设计许用值试验工作;试验数量的确定应综合考虑结构的重要性、试验数据的处理方法和设计许用值影响因素的衡量方法。最后,通过某型民用飞机的具体案例结合所述的试验矩阵的构成要素,详细论述了民用飞机复合材料设计许用值试验矩阵的设计方法。     

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.     

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....     

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.