自旋成型装置的设计与数值模拟

基于旋压和惯性自旋压原理,设计出精密成型装置,应用有限元分析方法,数值模拟了非均匀壁厚工件成型的工艺过程,重点分析了金属变形区的等效应力和等效应变的变化情况,结果表明,单次多道自旋成型工艺合理,精密成型装置设计可行,具有一定的推广价值。     

密封套强力旋压成型工艺仿真过程研究

采用 simufact有限元软件进行数值计算,研究了某密封套的旋压成型工艺过程,得到了旋压过程中等效塑性应变及等效应力分布规律,分析了进给比对筒形件成型精度及旋压力的影响,即密封套旋压成型中间进程的等效塑性应变最大,进给比在一定范围内增大,壁厚偏差变大,成型质量变差。     

一种普通旋压工装工艺方案设计

本方案是在没有旋压机设备情况下,在普通车上设计的一种旋压工装与工艺方案。设计了一套夹具与旋压头固定车床联结装置,并对其工艺性进行了分析,实践表明,该套装置与工艺满足了一般零件的旋压成型加工的需要。工艺设备简单,节省材料,产品合格率高,为生产实践提供了一定的借鉴意义。     

旋压模零件模具体工艺改进

旋压模是分离机零件碟片旋压成型用工装，因此，旋压模零件模具体的硬度直接关系到碟片旋压成型后的质量。本文就设计改选模具体材料，提高硬度要求，原加工工艺无法适用，提出了工艺改进方案，经工艺实施，取得成功。     

一种用于锥筒形零件的简易旋压专用机床的改制

一些锥形回转体薄壁零件,传统的方法用钣金展开下料后用相应的模坯上整形后再焊接而成,费工又不美观.本次专用机床改制是用旧C6136A车床床头,增加旋压装置、液压装置及电气和液压控制装置改制成一种用于锥筒形零件的简易旋压专用机床.通过对旋压加工工艺、旋压机床的机械结构、液压及电气控制及旋压机床的使用及工艺分析,制作一种实用可行的旋压设备,一次旋压成型,不需焊接,提高产品生产效率及质量,降低生产成本.类似形状的锥形回转体薄壁零件加工,只需更换模具及调整旋压装置移动的角度.     

导弹头旋压成型机理及成型质量研究

旋压作为回转体零件常见的加工方式,其优越性已广泛应用于航空航天。通过数值模拟方法研究了304不锈钢材料导弹头的旋压成型机理及其成型质量。采用单旋轮单道次一次成型工艺,首先根据剪切旋压体积不变原理设计了胚料尺寸,然后通过ABAQUS/Explicit建立了导弹头旋压有限元模型,根据模拟结果分析了其应力应变的分布状态,并分析了其壁厚沿周向以及径向的分布规律。最后分析了不同工艺参数对其成型质量的影响规律。     

发动机多楔皮带轮旋压工艺的研究

针对发动机多楔皮带轮大变形成型工艺问题,对塑性变形理论、多楔皮带轮材料本构模型及材料间摩擦类型等方面进行了阐述,对多楔皮带轮旋压过程中的毛坯、旋轮、芯模、尾顶进行了三维建模与装配,并对各零件之间的相对运动进行了分析。根据皮带轮楔型结构特征,基于Deform软件和刚塑性模型,提出了采用冲压和4道旋压工艺的多楔皮带轮成型方案。进行了有限元数值仿真,分析了各道旋压工序的实时动态应力应变状态及成型缺陷。通过模具试制和实际加工,对冲压和4道旋压工艺的方案进行了验证。研究结果表明:多楔带的齿槽和齿状填充饱满,加工的工件外形尺寸与零件图基本吻合,成型效果较好;该旋压工艺方案能较好完成多楔皮带轮成型加工。     

超长圆锥管拉拔-旋压联合成形加工的研究

研究了拉拔—旋压联合成形工艺的加工原理 ,研制了用于超长圆锥管拉拔—旋压加工的旋压装置及其控制系统 ,分析了工艺参数对加工质量的影响。工艺试验表明 ,拉拔—旋压联合成形工艺结合了拉拔工艺和旋压工艺的优点 ,特别适合超长圆锥管的加工。     

旋压法制皮带轮

图1所示系冷凝式柴油机中的铁皮V形皮带轮,V形槽的成型,我们采用车床旋压工艺获得成功。成型工艺过程: 剪圆片料——冲压成型坯件——划线钻孔(3-φ8.5)——退火——一次旋压(旋压前切去多余坯料,用R5滚轮)——退火——二次旋压成型(切去多余坯料,用R2.4滚轮)——车φ100孔。     

卡门曲线回转体旋压工艺参数优选试验研究

针对生产卡门曲线薄壁回转体零件旋压成型中存在的大端不贴模、拉裂、外表面起皮等旋压缺陷,确定了旋压工艺方案,从旋轮工作角、进给比及材料热处理等角度进行了不同工艺参数的试验研究,通过试验找出了最优的旋压工艺参数.试验结果对提高旋压件质量有良好的指导作用.     

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。     

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.     

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.     

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。     

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.     

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.