后轮罩封板翻边工艺优化研究

以汽车后轮罩封板为研究对象,对其翻边成形工艺进行分析,指出翻边缺陷产生的实质是翻边边缘切向应变的绝对值超过成形极限;以减小翻边边缘处切向应变绝对值为优化指标,对影响翻边成形性能的三个工艺参数:压边力、摩擦润滑条件、模具间隙进行正交设计,运用有限元模拟软件Dynaform进行模拟试验得到优化工艺方案;最后对优化方案进行实验验证,结果表明,数值模拟试验是可靠的,得到的优化方案可以避免翻边成形中的缺陷。     

发动机环形火焰筒头部帽罩成型工艺改进

本文阐述了发动机环形火焰筒头部帽罩的结构特征、加工难点以及工装的设计,针对零件成型工艺、冲孔、翻边和车加工工艺做了具体的分析,提出了相应的解决措施,解决了薄壁、钣金零件双曲面成型、大直径高翻边成型以及复杂型面钣金件的车加工问题,为此类钣金零件的加工积累了成功的经验。     

包边原理及质量控制要点分析

正包边历史较短,且包边方式及各种各样的关系,所以与其他设备相比没有统一规格,这是包边的现状。1.包边原理及种类包边工艺是为了结合内外板或是把一张板材,利用模具把翻边折压的工序。主要适用于车身覆盖件,如车门内外板、发动机罩内外板、行李箱内外板、后背门内外板等。作为汽车制造焊装     

自润滑向心关节轴承翻边工艺改进

航空发动机制造过程中,部分自润滑向心关节轴承组合时合格率不高及翻边效果不稳定。通过比较国内外自润滑关节轴承翻边方法,分析关节轴承翻边时及翻边后检测的相关参数及加工方法,着手提高翻边轴承的加工合格率及稳定性,并固化相关工艺参数,形成一套完整的加工关节轴承翻边及检测方法。     

顶罩板折角模的设计

正1.零件工艺分析图1所示为三菱空调顶罩板,材料为Q235A,板厚为0.6 mm。零件的冲压工艺顺序为:切角冲孔→拉深切角→折边翻孔压窝→折角。其中折角要求把顶罩板上4角4个R10 mm处2.3 mm长的直边折出来。     

临工LG8系列压路机

临工LG8系列压路机吸收了现有振动压路机的成熟技术,结合国内道路建设的特点,在技术参数上进行了优化,具有优秀的性价比。动力系统选用上柴D6114系列发动机,动力性能强,扭矩大,噪声低。驱动桥选用装载机的驱动桥,技术成熟,性能可靠。发动机罩流线型的发动机罩与整车结构非常协调,并能够实现左右侧罩向上翻,后罩向后翻,从而能够实现发动机的全方位检修。     

汽车发动机罩外板工艺与模具的研究设计

受到经济全球化的影响，越来越多的国家开始了解自主创新的重要性。我国的汽车行业经过几十年的发展，综合实力得到了很大程度的提高。然而，要真正融入世界汽车工业体系甚至是在汽车工业领域处于领先的地位，仅仅依靠外来设计进行生产无疑是做不到的。目前国内的一些汽车厂家已经逐渐走上了自主研发道路。汽车覆盖件设计是汽车设计的重要环节。作为汽车覆盖件的一部分，发动机罩外板的设计也是不可忽视的问题。本文从发动机罩外板的工艺与模具两个方面对发动机罩外板的设计进行研究探讨。     

基于CATIA平台的汽车覆盖件翻边成形过程同步模拟

基于CATIA平台,开发了汽车覆盖件翻边成形模拟系统。系统将结构设计中模具结构行程图思想引入翻边成形模拟中,综合考虑了翻边方向、驱动角与翻边行程对实际工艺的影响,该系统可真实反映翻边运动关系,以及翻边镶块交刀对翻边成形过程的影响,并在求解计算前通过动画演示的方式进行运动仿真,对工具运动进行干涉检查。同时,系统将CAE模型作为CATIA的特征集成于CAD平台上,实现了CAD设计模型与CAE分析模型的同步更新,避免了平台转化过程中模型数据丢失与精度损失,缩短了CAE反复建模的时间,提高了设计效率。最后通过汽车后围外板的翻边实例分析,验证了系统的准确性和稳定性。     

CAE技术在汽车前轮罩后板拉延模具设计中的应用

汽车前轮罩后板属于典型的汽车冲压件,与一般冲压件相比,具有形状复杂（多位空间曲面）、拉延轮廓尺寸大、拉延深度深、材料薄、表面质量要求高等特点。其生产过程一般由拉延、修边、整形翻边、侧修边、侧冲孔等多道冲压加工工序完成。其中,拉延工序是制造轮罩后板的关键工序,它直接影响产品质量、材料利用率、生产效率及良品率。为了实现拉延或创造良好的拉延条件,必须合理设计冲压方向、工艺补充部分形状和尺寸以及压料面形式、拉延筋布置、毛坯尺寸和形状等重要工艺因素。     

复合填充芯材的优化设计及其应用研究

为进一步提高汽车发动机罩填充芯材的缓冲吸能性能,将轻质、缓冲性能佳的EPP泡沫填充到铝蜂窝芯材中,采用代理模型和多目标优化算法求解获得填充芯材的参数优化解,最终的优化参数为铝蜂窝胞元边长3mm、蜂窝壁厚0.06mm、EPP泡沫密度40kg/m3,并开展了低速冲击试验验证优化结果的可靠性。将优化后的填充芯材应用于汽车发动机罩中,研究其对汽车行人保护性能的影响及其轻量化效果,研究结果显示,新发动机罩的行人头部损伤值降低了(13.5～51.8)%,加速度峰值降低了(9.4～39.2)%,所有碰撞点均没有发生二次碰撞,并且在不降低发动机罩机械性能的前提下,新发动机罩比原发动机罩减轻了23.8%,表明芯材填充对提高汽车发动机罩的行人保护性能及轻量化效果明显。     

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.     

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.     

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.     

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。     

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.     

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...