Cu-3镍铜合金砂带磨削试验研究

分析了Cu-3镍铜合金砂带磨削加工过程中,砂带粒度和磨削用量的不同对磨削加工效率、工件表面质量和砂带磨损的影响。采用氧化铝磨料砂带在不同的砂带线速度或磨削压力下对镍铜合金进行了工艺试验,对材料去除量、工件表面粗糙度和砂带磨损量进行了测量。研究表明:增加砂带线速度和磨削压力可在一定程度上提高材料去除率和磨削比;随着磨削压力的增大,工件表面粗糙度呈增大趋势;随着砂带粒度的增大,工件表面粗糙度呈减小趋势;砂带线速度为25m/s,磨削压力为43N,砂带粒度为P240时,镍铜合金综合磨削效果最好。     

CBN砂带恒压力磨削玻璃钢试验

针对玻璃钢易切除、易烧伤的特点,采用3种不同粒度的CBN砂带对玻璃钢进行恒压力砂带磨削实验,分析了在磨削过程中不同的砂带粒度和磨削用量对砂带磨损和工件表面质量的影响。在磨粒切削加工模型的基础上,通过观察磨削前后玻璃钢表面微观形貌分析了玻璃钢的磨损机理。通过正交试验得到:随着砂带线速度和粒度号的增大,玻璃钢表面粗糙度呈减小趋势;材料去除率会随着砂带线速度和磨削压力的增加而增大,当砂带线速度v_s=25 m/s,磨削压力F=56N,粒度P=180#时,磨削效果达到最好。     

ZrO_2工程陶瓷砂带磨削实验及工艺研究

采用4种不同磨料的砂带对Zr O_2工程陶瓷进行对比磨削实验,并采用锆刚玉磨料的砂带进行正交试验,对材料去除量、工件表面粗糙度和砂带磨损量进行了测量,得出了Zr O_2工程陶瓷最佳磨削参数。文章分析了在对Zr O_2工程陶瓷进行砂带磨削加工过程中砂带粒度和磨削用量的不同对磨削加工效率、工件表面质量的影响。在磨粒切削加工模型的基础上,通过观察磨削前后陶瓷表面微观形貌分析了工程陶瓷的磨损机理。实验结果表明:随着磨削压力和砂带粒度的增大,工件表面粗糙度呈减小趋势;增加砂带线速度和磨削压力可在一定程度上提高材料去除率和磨削比,但超过临界值其表面易发生崩脆断裂;砂带线速度为19 m/s,磨削压力为15 N,砂带粒度为120#时,Zr O_2工程陶瓷综合磨削效果达到最好。     

砂带磨削磨损性能试验研究

分析了砂带磨料种类、工件材料特性及磨削用量的不同对磨削加工效率和砂带磨损的影响,采用2种不同磨料的砂带分别对3种材料进行了工艺试验,对材料去除量和砂带磨损量进行了测量,揭示了砂带的磨损机理。研究表明:钛合金可磨削性较差,304不锈钢的可磨削性比钛合金好,45号圆钢最易于磨削;增加砂带线速度可在一定程度上提高材料去除率和磨耗比;陶瓷磨料比氧化铝磨料磨耗比大,因此磨削时可选择陶瓷砂带进行大余量加工;随着硬度比的增加,磨耗比呈现出先增大后减小的趋势,因此磨削时可根据磨削要求选择合适硬度磨粒的砂带进行磨削。     

电镀金刚石砂带磨削氧化铝陶瓷的试验研究

通过单因素试验分析了氧化铝陶瓷加工中工艺参数对磨削效率的影响;通过正交试验研究了试验因素对磨削效率的影响以及砂带结构参数对磨削表面粗糙度的影响,并确定合理工艺参数。结果表明,砂带线速度增加,磨削效率增加,砂带线速度过大,磨削效率下降;磨削效率随磨削压力的增加而提高,磨削压力增大到一定值以后,磨削效率明显下降;工件进给速度增加,磨削效率增加,进给速度增加到2.2mm/s以后,磨削效率下降较快。正交试验表明:工艺参数对磨削效率的影响大小为:磨削压力工件进给速度砂带线速度;磨削表面粗糙度随着砂带粒度号和植砂密度的增加而下降。     

基于支持向量机和遗传算法的柔性砂带磨削刀具状态研究

砂带磨削过程中,磨粒的磨损会影响材料去除率以及零件表面质量.针对砂带磨削过程中刀具状态预测问题,采用基于支持向量机和遗传算法的预测模型实现砂带磨损状态的有效预测,并对预测效果进行仿真验证.简化砂带磨削工艺,构造磨削工艺数学模型.引入K值最近邻算法作为遗传算法的适应度函数,构造了基于支持向量机和遗传算法的预测模型.采用MATLAB数学软件对砂带进行实时仿真计算,并与采集的实验数据进行对比和分析.结果 显示,基于支持向量机和遗传算法的预测模型,预测的不同加工参数下的砂带磨损量与实验数据基本吻合,误差不超过8％.采用基于支持向量机和遗传算法的预测模型可以准确预测砂带的状态,有助于提升砂带利用率及精加工质量.     

砂带磨削装置的设计与应用

一、国外砂带磨削的概况砂带磨削工艺,就是将环形砂带套在接触轮、导轮或张紧轮的外圆上,在张紧状态下,使高速旋转的砂带表面与工件的加工表面相接触,并在一定的压力作用下,以产生的相对摩擦运动(切削运动)对工件表面进行磨削加工的一种方法。砂带和砂轮一样,同属于一种多齿微刃型的切削工具,其加工特性基本相同,所不同的只是形状各异罢了。随着粘结剂的发展,耐水树脂砂带的出现,特别是在国外采用高压静电植砂新工艺的结果,使砂带的磨削性能得到显著提高,从而为砂带磨削在机械制造工业中广泛地推广使用创造了条件。     

砂带振动磨削圆度误差的试验研究

砂带振动磨削是将砂带磨削、研抛和振动加工合起来 ,形成复合加工的一种新型精密加工和超精密加工方法。砂带振动磨削采用开式砂带磨削的加工方式 ,如图 1所示。接触轮可带动砂带沿轴向作一定频率的振动。接触轮可以随工件一起转动 ,也可以固定。一、试件的设计及加工方式的选择　　 2 砂带磨削时间与圆度误差的关系由上述试验可以得出如下结论 ,在政党的加工条件下 ,砂带振动磨削可以降低圆度误差。对于 φ2 5ｍｍ的 4 5钢工件 ,先精车 ,然后用砂带磨削 ,其圆度误差可由精车后的 10 μｍ减小到 1～ 2 μｍ。砂带振动磨削圆度误差的试验研…     

陶瓷CBN砂轮磨削镍基铸造高温合金K418磨削力研究

系统开展了陶瓷结合剂CBN砂轮磨削K418的试验研究,测试了不同砂轮线速度、工件进给速度及切深条件下的磨削力。通过对试验数据的分析处理,得到上述3个工艺参数对磨削力、力比及磨削比能的影响规律。并拟合出了陶瓷结合剂CBN砂轮磨削基铸造高温合金K418时磨削力的经验公式,该公式估算误差低于10%。磨削力和力比均随着工件进给速度、切深和当量磨削厚度的增大而增大,随砂轮线速度的减小而增大。随着当量磨削厚度的不断增加,磨削比能呈下降趋势。     

超声砂带磨削TiC-TiB2复合陶瓷表面质量试验研究

任何机械加工方法都不能获得理想表面,而要实现工件高精度、低表面粗糙度值、低残余应力、低硬化层的表面高质量要求,这是现代磨削技术的重要发展趋势。通过超声砂带磨削与普通砂带磨削的对比试验,研究分析了砂带粒度、磨削深度、砂带线速度、工件进给速度等加工工艺参数对工件表面质量的影响。实验结果表明:采用细粒度的金刚石砂带以及合理的磨削工艺参数可以降低工件表面粗糙度和减少磨削裂纹,这在生产中具有重要的实际意义。     

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...