二硫化钼填充高岭土基矿物聚合物复合材料的摩擦学性能研究

研究了MoS2填充量对高岭土基矿物聚合物复合材料的力学性能和摩擦磨损性能的影响,利用XRD、SEM分析了材料的微观结构和磨损表面形貌。结果表明,填充MoS2后矿物聚合物材料的力学性能会有一定程度的降低,但其摩擦磨损性能可以得到有效改善,当MoS2体积分数为30%时,摩擦因数和磨损率均达到最低,分别为0.423和1.23×10-4mm3/(N.m)。研究发现,当二硫化钼含量较低时,磨损机制主要是磨粒磨损;当二硫化钼含量较高时,磨损机制是磨粒磨损和粘着磨损。     

聚苯酯填充聚四氟乙烯复合材料摩擦学行为研究

采用聚苯酯（Ekonol）、Ekonol／PAB纤维增强聚四氟乙烯（PTFE）制备利用转移膜润滑的摩擦副材料，并研究了两组材料在于摩擦条件下与9Cr18轴承钢对摩时的摩擦学性能；运用扫描电镜分析了两组材料磨损表面形貌和磨损机理。结果表明：随着Ekonol含量的增大，Ekonol填充PTFE复合材料的摩擦因数逐渐增大，当Ekonol质量分数超过25％时摩擦因数略有下降，磨损方式由以犁削磨损为主转变为以疲劳磨损为主；而Ekonol／PAB纤维填充门FE复合材料的摩擦因数，随Ekonol含量的增大而增大，磨损方式由以粘着磨损为主转变为以疲劳磨损为主。Ekonol／PAB纤维填充PTFE复合材料的摩擦学性能优于Ekonol填充PTFE复合材料。     

碳材料填充PTFE复合材料摩擦磨损性能

利用 MM-200 型磨损试验机考察了石墨、碳纤维、硬碳和软碳填充 PTFE 复合材料的摩擦磨损性能,采用扫描电子显微镜观察分析磨损表面形貌及磨损机制.结果表明,碳材料可以不同程度地提高 PTFE 的耐磨性,它们对PT-FE 耐磨性的提高程度各不相同,其中以硬碳填充 PTFE 复合材料的磨损质量损失最小,石墨填充 PTFE 复合材料的磨损质量损失较大;不同填充材料对 PTFE 摩擦因数的影响各不相同,其中石墨填充 PTFE 的摩擦因数较小.石墨、软碳填允复合材料磨损机制以粘着磨损为主,硬碳、碳纤维复合材料,则表现为粘着磨损和磨粒磨损.     

聚四氟乙烯纳米复合材料的制备及其力学和摩擦学性能

以添加表面活性剂的水为溶剂,采用溶剂混合法制备纳米 Al2 O3填充聚四氟乙烯（PTFE）复合材料,研究其力学性能和摩擦学性能,并与乙醇中分别制备纳米 Al2 O3填充 PTFE 复合材料进行比较。结果表明：在相同 Al2 O3填充比例下,水中制备的复合材料的拉伸强度和硬度要低于乙醇中制备的复合材料,而断裂伸长率却要高于乙醇中制备的复合材料。在200 N 和干摩擦条件下,当纳米 Al2 O3质量分数为1％～5％时,水中制备的复合材料的磨耗量要低于乙醇中制备的复合材料,并较纯 PTFE 磨耗量下降了1～2个数量级;且水中制备的复合材料的摩擦因数也要低于乙醇中制备的复合材料。复合材料磨痕处 SEM显示复合材料的磨损机制为黏着磨损和磨粒磨损。     

有机填料填充聚四氟乙烯复合材料摩擦学及力学性能

采用共混-冷压-烧结-整形的工艺制备有机物填充聚四氟乙烯(PTFE)复合材料,考察相同含量的不同有机填料对PTFE复合材料力学性能和摩擦学性能的影响。结果发现,加入有机填料后,复合材料的拉伸强度降低,但硬度和压缩强度均提高;有机填料有效地改善了PTFE复合材料的摩擦学性能,其中,质量分数15%聚苯酯填充的PTFE复合材料减摩效果最好,质量分数15%聚酰亚胺填充的PTFE复合材料的耐磨损性能最优。相比之下,质量分数15%芳纶填充的PTFE复合材料摩擦磨损性能及力学性能最好,其耐磨损性能较纯PTFE提高了近400倍,而摩擦因数仅为纯PTFE的84%。其原因在于芳纶的加入有效地改变了摩擦机制,能形成均匀连续的转移膜,进而降低了磨损。     

硫酸钙晶须填充PTFE复合材料的摩擦学性能研究

用硫酸钙晶须(CSW )填充改性聚四氟乙烯(MVE),采用模压成型工艺制备不同硫酸钙晶须含量的PTFE/CSW复合材料;利用摩擦磨损试验机研究硫酸钙晶须对PTFE/CSW复合材料摩擦学性能的影响,利用扫描电子显微镜对PM复合材料的磨损表面进行微观分析.结果表明:填充硫酸钙晶须提高PTFE复合材料的耐磨损性能,但复合材料的摩擦因数略高于纯PTFE;纯PTFE的磨损机制为黏着磨损,而PTFE/CSW复合材料的磨损机制为轻微磨粒磨损和黏着磨损共同作用.当硫酸钙晶须质量分数大于10%时,PTFE/CSW复合材料的磨损机制逐渐转变为严重的磨粒磨损.     

不同填料填充PTFE复合材料的力学及摩擦磨损性能

采用共混-冷压-烧结制备工艺制备MoS2、聚酰亚胺和芳纶纤维填充的聚苯酯/聚四氟乙烯(POB/PTFE)复合材料,在MRH-3型高速环块摩擦磨损试验机和WD-W-200型万能材料试验机上考察不同填料对POB/PTFE复合材料力学性能和摩擦学性能的影响。实验结果表明:聚酰亚胺和芳纶与POB的协同润滑与减磨效应降低了POB/PTFE复合材料的摩擦因数与磨损量,并提高了复合材料的压缩模量和压缩强度;与MoS2/POB/PTFE复合材料相比,聚酰亚胺和芳纶纤维填充的POB/PTFE复合材料有着更好的力学性能、摩擦稳定性和耐磨性。     

纳米粒子和聚四氟乙烯填充UHMWPE复合材料的摩擦磨损性能研究

以纳米氧化锌(ZnO)和纳米蒙脱土(MMT)及聚四氟乙烯(PTFE)作为复合填料,通过热压成型工艺制备了纳米ZnO-MMT及PTFE填充超高分子量聚乙烯(UHMWPE)复合材料,采用销-盘式摩擦磨损试验机考察了纳米粒子对复合材料摩擦磨损性能的影响,用扫描电子显微镜观察了复合材料磨损表面形貌。结果表明当PTFE和MMT的填充量均保持为质量分数6%,填充纳米ZnO质量分数为4%~6%时的复合材料可获得较好的摩擦磨损性能,与不含纳米ZnO的复合材料相比,其摩擦因数最低下降了11.1%,而磨损率下降了83.3%。当复合填料中纳米ZnO含量较低时,复合材料的磨损机制主要表现为不同程度的粘着磨损,但当复合填料中纳米ZnO含量较高时,复合材料的磨损机制主要表现不同程度的粘着磨损和磨粒磨损,同时其复合材料的摩擦磨损性能出现了恶化现象。     

低含量磷片石墨填充改性PTFE复合材料的摩擦磨损性能

为了改善聚四氟乙烯高磨耗的缺点,通过冷压烧结成型工艺制备4种低含量鳞片石墨填充改性聚四氟乙烯(PTFE)复合材料,探究其在较高载荷(0.8 MPa)及不同转速下的摩擦磨损情况。采用三维视频显微镜观察样品的表面磨痕深度,借助扫描电镜观察摩擦表面形貌并分析磨损机制。结果表明:在较高载荷下石墨填充PTFE复合材料的摩擦因数和体积磨损率都较纯PTFE有一定程度的降低;且当石墨填充质量分数为5%时,复合材料的摩擦因数和体积磨损率降到最低,在载荷为0.8 MPa、转速为80 r/min时较纯PTFE分别降低了19.7%和84.25%;在较高载荷下,随着石墨含量的增大,复合材料的磨损机制逐渐由犁耕磨损向黏着磨损转变,且当石墨质量分数为10%时,出现轻微的疲劳磨损。     

PTFE基三层滑动轴承材料与不同材料配副时的摩擦学特性

PTFE基三层滑动轴承复合材料与不同材料组成的摩擦副有着不同的摩擦学特性,研究这些摩擦副的摩擦学特性,对于优化摩擦副配副材料具有重要的实用价值。研究PTFE基三层复合材料与钢铁材料、有色金属以及聚合物材料进行配副时的摩擦磨损性能,通过扫描电镜观察磨损表面的微观形貌,分析不同摩擦副的摩擦磨损机制,并给出摩擦副配副的优选结果。结果表明:PTFE基三层滑动轴承材料与钢铁材料以及聚合物材料配副时,其磨损机制为剥层磨损,摩擦学性能较好;而与有色金属配副时,其磨损机制为黏着磨损,摩擦学性能较差。     

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...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

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.     

INDUSTRIAL ENGINEERING AND VISUALISATION-A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very important role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

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...