基于电铸技术制造精密金属微器件

鉴于电铸技术在实现精密金属微结构/器件方面所展现出的独特优越性,依托其为主要工艺手段,以制造微十字和微圆柱两种不同尺度的精细金属微器件为目标,开展试验研究,并借助扫描电镜对所得微器件的形貌质量进行评价。结果表明:基于电铸技术能制造出良好形貌且具备较高廓形精度的金属微器件。     

内置微通道T/R组件壳体设计及试验研究

为了降低界面热阻对微通道散热性能的制约,提出了一种组件壳体内置微通道散热单元的设计架构,以满足新一代高功率芯片T/R组件的热控需求.对内置微通道的传热特性进行数值仿真分析,优选出最佳结构参数组合.基于优选设计参数,整合UV-LIGA微细加工技术、精密扩散焊接技术及微组装技术,完成内置微通道散热单元T/R组件的模拟样件研...     

金属微成形过程中微尺度效应与相似评估

微尺度效应是金属微成形过程中特有的现象,也是深入研究微成形工艺和微尺度变形规律的瓶颈问题。通过对大量试验结果的分析比较,提出将微尺度效应分为材料本征微尺度效应和工艺条件微尺度效应的新的分类方法;从微成形工艺系统角度出发,分析微尺度效应的动态性和相关性;从本构理论出发,分析产生微尺度效应的原因;在相似性科学的基础上提出了相似精度的概念,作为评估微尺度效应的相似性评价指标,并给出考虑动态性和关联性时的相似精度表述。利用已有的试验数据,举例说明以上评估指标和评估方法的应用,结果表明,所提出的微尺度效应分类具有实际工程意义,应用所提出的评估方法得出的结论与已有试验结果相吻合。这些关于微尺度效应的分类和评估方法还可推广应用到其他微系统的评估中。     

微/小通道冷却技术的工程化应用

微/小通道冷却是工程领域应对电子设备"热障"的最重要的强化传热技术之一。文中阐述了微/小通道冷却技术的概念和原理以及微尺度流动、对流传热的微尺度效应和入口段效应,并详细讨论了开展微/小通道冷却技术工程化研究的若干关键问题,从而澄清了微/小通道冷却技术在目前阶段工程化应用方面的思路,为开展微/小通道换热器的工程研究和设计提供了有益的帮助。     

高热流密度电子设备散热技术

高发热密度电子设备对散热提出了更高的要求，本文就平板热管、微通道、液体喷淋冷却等典型的高性能散热技术及其应用情况进行了讨论和综合分析。     

应用TAGUCHI法对微拉深成形有限元模拟结果的误差分析

为考察基于传统本构模型和求解算法的有限元程序模拟金属微成形过程的适应性,设计正交试验,应用自行开发的板料成形有限元程序ARVIP-3D对微成形和等比放大10倍的常规成形进行模拟计算,并根据质量工程中的TAGUCHI法,参考信噪比的概念,对材料参数和工艺条件等因素对两类相似拉深的模拟结果误差进行了分析。结果表明：微成形中的尺度效应主要是成形机理与常规成形不同而引起的,基于传统本构模型和求解算法的有限元程序不能正确模拟微成形过程,但可以模拟出摩擦引起的尺度效应;宏微观尺度的成形模拟结果误差主要来自于浮点运算的误差,但几何和力学条件的处理也给模拟误差带来了影响。因此,在开发适合于微成形模拟的新型有限元程序中,不仅要考虑本构模型的特殊性,几何和力学条件的相关处理算法也应进行改进。     

金属微滴三维打印成形数据处理软件的设计开发

金属微滴三维打印成形技术是一种新的快速分层制造方法,为了获取零件模型的离散化层面数据,实现零件的分层打印制造。依据金属微滴三维打印成形工艺原理,利用Visual C++6.0和Open GL,在Windows XP平台上,开发出面向金属微滴三维打印成形工艺的数据处理软件。利用该软件得到的成形数据信息,以Sn60/Pb40合金为试验材料,在280℃喷射温度、100k Pa喷射压力和200μm熔滴直径下,进行了打印沉积试验,打印成形结果与零件模型吻合较好,验证了数据处理软件的可行性,为金属微滴三维打印成形技术的发展奠定了基础。     

金属微滴逐层光栅扫描打印成形效率影响研究

为了提高金属微滴打印成形工件的效率,分析了逐层光栅扫描模式下影响打印成形效率的主要因素,计算了金属微滴在不同旋转角度(θ)光栅扫描路径下,打印成形同一个层面所需的喷射启停次数、跳转路径、微滴沉积路径和总平台运动路径等。结果表明:在设定相匹配的微滴喷射频率与沉积平台运动速度条件下,减少喷射启停次数和缩短空跳转路径是提高成形效率的主要途径。依据上述研究结果,采用D=0.2mm的Sn60/Pb40微滴打印成形微小多孔零件,耗时约为4 h 20 min,显著提高了打印成形零件的效率。     

3D打印微通道液冷板设计及实验研究

机载电子设备集成度与功率越来越高,电子元器件的冷却及可靠性面临严峻的挑战.本文介绍了3D打印微通道液冷板的换热机理、结构设计、仿真优化过程,并进行了微通道液冷板的换热性能实验测试.实验结果表明微通道液冷板具有较强的换热性能,能够满足热流密度50 W/cm2器件的散热需求,3D打印出的微通道结构完整,污染度满足设计及系统...     

含微通道网络的再生支架3D打印成形工艺和系统及试验研究

3D打印技术在构建个性化的人工组织和器官方面具有独特优势和发展潜力,然而目前在构建具有优良代谢性能的人工组织方面也还存在很多技术壁垒。在秉承3D打印技术优势基础上,综合考虑生物材料的反应成形特性,提出一种能够直接成形微尺度中空纤维,再三维叠层制造,从而直接获得内含微通道网络的再生支架的3D打印成形工艺;基于管材无模拉伸理论,定量分析微尺度中空纤维在被三维搭接过程中的拉伸变形,为工艺优化和参数调控奠定了理论基础;在给出相应成形系统的关键组成和技术要点基础上,进行了三维再生支架的制备试验及性能测试与分析。试验结果表明,提出的工艺及系统存在巨大的应用潜力,为有效解决人工再生组织血管化问题提供了一种全新的技术途径。     

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...     

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.     

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。     

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。     

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。     

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.     

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.     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

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.