高速铣削GH4169镍基高温合金切削温度的研究

为了研究GH4169镍基高温合金在高速铣削过程中不同切削用量对切削温度的影响,采用正交试验法对其进行切削仿真,并对铣削加工仿真结果进行分析,得到切削用量与切削温度的关系。为验证仿真结果的合理性和准确性,进行了GH4169镍基高温合金高速铣削加工试验,对比分析高速铣削试验和高速铣削加工仿真的结果,验证GH4169镍基高温合金高速铣削仿真模型的准确合理。在已确定的加工仿真模型基础上进行单因素试验,研究不同切削用量对切削温度的影响。结果表明：在切削速度、每齿进给量和背吃刀量均增大的条件下,铣削温度都逐渐上升,但增长速率呈下降趋势。     

基于响应曲面法的GH4169镍基高温合金干车削参数优化试验

GH4169镍基高温合金具有优异的高温强度、塑性、耐腐蚀性和抗疲劳性能,广泛应用于制造航空发动机、燃气轮机的涡轮叶片等高温部件,而其热导率低、导热性差、加工硬化倾向大,是典型的难加工材料。采用正交试验法和响应曲面法,研究了涂层硬质合金刀具干式车削GH4169镍基高温合金的切削力和已加工表面粗糙度。通过正交实验研究了加工参数对切削力和已加工表面粗糙度的影响;通过回归分析建立了加工参数与切削力、已加工表面粗糙度的回归方程,并揭示了切削力、表面粗糙度与切削参数的响应关系;基于正交试验数据,通过多目标规划,优化得到了涂层刀具车削加工GH4169镍基高温合金的切削参数。     

基于标准粒子群算法的GH4169高速铣削表面粗糙度研究

采用单因素和正交实验法,研究了整体硬质合金刀具高速铣削GH4169高温合金时切削参数对表面粗糙度的影响规律,结果表明,每齿进给量对表面粗糙度的影响十分显著,铣削速度和铣削深度对表面粗糙度的影响较小;基于标准粒子群算法建立了表面粗糙度与切削参数之间的经验公式,并对经验公式进行了实验验证,结果显示,基于标准粒子群算法建立的经验公式能有效预测GH4169高温合金高速铣削过程中的表面粗糙度,为铣削参数优化、铣削表面质量控制提供了依据。     

GH706高温合金铣削力试验研究

针对高温合金材料GH706切削加工性差的问题,通过对高温合金GH706的铣削试验,研究切削速度、每齿进给量和轴向切削深度对铣削力的影响。通过单因素试验得到了切削参数与铣削力的变化曲线;用正交实验法和多元线性回归分析方法建立了铣削力经验公式,并进行了试验验证。试验结果表明,铣削力经验公式可以有效地预测铣削力的大小;铣削力随着轴向切深、每齿进给量的增加而增加,而随着切削速度的增加有减小的趋势。     

GH706高温合金削力试验研究

针对高温合金材料GH706切削加工性差的问题,通过对高温合金GH706的铣削试验,研究切削速度、每齿进给量和轴向切削深度对铣削力的影响.通过单因素试验得到了切削参数与铣削力的变化曲线;用正交实验法和多元线性回归分析方法建立了铣削力经验公式,并进行了试验验证.试验结果表明,铣削力经验公式可以有效地预测铣削力的大小;铣削力随着轴向切深、每齿进给量的增加而增加,而随着切削速度的增加有减小的趋势.     

高温合金GH4169高速铣削仿真加工与分析

利用Third wave AdvantEdge FEM软件建立了三维切削模型,对高温合金GH4169进行了高速铣削模拟加工.通过模拟分析得到了切削速度、每齿进给量、切削深度对切削热的影响规律;试验中发现,切削速度的变化对切削温度的影响规律与高速切削理论有出入,切削速度的变化对切削温度的影响较每齿进给量和切削深度大.     

GH4169插铣参数对刀具寿命影响规律及磨损形貌研究

为了研究GH4169插铣加工中切削参数对刀具寿命的影响规律,采用正交试验法,使用整体硬质合金刀具进行GH4169的插铣试验。运用多元线性回归分析的方法建立刀具寿命的经验公式,分析了切削参数对刀具寿命的影响规律;并采用电子扫描显微镜(SEM)对刀具在不同阶段的磨损形貌进行观测。结果表明:在插铣加工高温合金GH4169过程中,铣削速度对刀具寿命的影响最大,其次是每齿进给量和径向切深。     

高效铣削镍基高温合金GH4169的有限元数值模拟

在DEFORM软件中,根据实际加工情况建立整体硬质合金立铣刀加工镍基高温合金GH4169的三维有限元仿真分析模型。针对镍基高温合金GH4169加工效率低和切削刃磨损严重的问题,采用单因素试验法仿真探讨了切削用量(v、f_z、a_p、a_e)对切削力和切削温度的影响规律。获得了能有效提高镍基高温合金GH4169加工效率的切削用量,为实际加工中实现高效铣削镍基高温合金切削用量的选择提供依据。     

基于正交实验的玻璃陶瓷铣削加工表面质量研究

采用正交试验法研究球头铣刀铣削加工牙科玻璃陶瓷时铣削参数对零件加工表面粗糙度的影响。设计了以铣削速度、每齿进给量、切削深度、径向切削宽度为主要因素的正交试验。通过极差分析方法研究了切削参数对表面粗糙度的影响规律,明确了主要影响因素。结果表明:各因素的影响程度从大到小依次为每齿进给量、径向切削宽度、铣削速度、切削深度。并建立了牙科玻璃陶瓷铣削加工表面的表面粗糙度预测模型。     

基于响应曲面法的GH4169铣削参数优化及实验研究

机械加工的表面质量会极大地影响零部件的使用寿命。该文以降低镍基高温合金GH4169加工过程中的表面粗糙度为目标，对镍基高温合金GH4169的铣削参数进行优化。基于响应曲面法分析了铣削参数(转速、进给量、切削深度)对表面粗糙度的影响规律，建立了铣削参数与表面粗糙度之间的二次多项式模型并进行了验证，确定了降低表面粗糙度的最优工艺参数组合。研究结果表明，当A=928.34 r/min,B=243.35 mm/min,C=0.2 mm时，粗糙度可达到0.143μm。采用最优参数组合进行加工实验，并对铣削加工后的表面粗糙度进行测量，得出粗糙度实测值与模型预测值的相对误差为0.2%,可见所建立的模型是准确的。可满足某些航空航天高精度零部件表面质量特性，因此该模型对GH4169铣削加工具有指导意义。     

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...     

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。     

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...     

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。     

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.     

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.     

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.