基于UG的直齿圆柱齿轮参数化精确三维建模

详细介绍了一种利用UG的表达式和规律曲线功能建立直齿圆柱齿轮模型的方法。该方法绘制了精确的齿轮过渡曲线,并且生成的齿廓各段曲线不需要任何修剪便可直接建立精确的齿轮模型,该方法也适用于齿数大于41时的齿轮建模。通过改变模数和齿数,生成的模型可以自动更新,实现了建立模型的真正参数化。     

基于MASTERCAM的渐开线圆柱齿轮数控加工仿真

在齿轮加工中渐开线轮廓加工精度将直接影响到齿轮的性能,论文提出了用AutoLISP语言绘制渐开线齿廓的方法,实现了渐开线轮廓的参数化设计,可以依据齿轮的精度要求来绘制相应的渐开线齿廓。然后在MasterCAM环境下进行了渐开线圆柱齿轮的数控加工仿真并生成了数控加工代码。实验结果证明,该方法提高了齿轮轮廓绘制以及数控加工的精度。使用该方法进应用于生产加工,可以改善齿轮的性能,同时也提高了生产效率。     

Solid Works环境下的齿轮精确三维造型设计

详细介绍了在Solid works中实现圆柱齿轮精确三维造型的方法和技巧。重点讨论了齿廓曲线的计算方法及其与齿轮加工刀具的关系，分别讨论了齿廓曲线渐开线部分和齿根过渡曲线部分的曲线方程。并编制出了齿廓曲线的计算程序。最后在Solid works中绘制出了直齿圆柱齿轮的精确三维模型。     

基于Solidworks和Excel渐开线齿轮三维精确建模研究

针对目前齿轮建模方法中存在的缺陷,提出了一种比较简单、易学的精确建模方法,通过研究标准渐开线圆柱齿轮齿廓渐开线和齿根过渡线,建立了参数方程.结合Excel和Solidworks软件直接生产渐开线和齿根过渡线,再通过坐标变换调整曲线得到满足要求的齿轮齿廓,完成了齿轮的三维实体精确建模设计.     

非圆行星齿轮马达轮系特殊结构的设计

提出了一种高阶非圆行星齿轮马达,相比于波兰SOK马达,高阶非圆齿轮马达径向力平衡,排量大,脉动小,性能更优。如何确定齿轮副中各非圆齿轮的节曲线和齿廓是设计非圆齿轮的关键。本文首先依据非圆齿轮的啮合原理,得出封闭节曲线的方程式,确定在节曲线上均匀分布的轮齿的位置,并通过利用产形齿轮与非圆柱齿轮啮合关系来确定非圆柱齿轮的齿廓。通过MATLAB编程软件对相关参数方程进行相应的计算,快速的计算出准确的非圆齿轮副的节曲线和齿廓。最后用实例验证了该方法的可行性。     

基于机器视觉和局部图像分析的齿轮中心定位

在机器视觉测量中小模数直齿圆柱齿轮时,由于受摄像头视野限制,无法拍摄完整齿轮图像。因此,齿轮的中心定位成为直齿圆柱齿轮高精度测量的关键步骤。文章针对此问题,提出利用有约束条件的固定半径最小二乘法拟合求圆心的方法,多次迭代逼近齿顶圆过渡带,通过得到精确的齿顶圆边界,逐步修正齿轮中心,从而提高了检测齿轮中心位置的准确度。在此基础上,将已确定的齿轮中心,代入极坐标公式,根据渐开线齿轮各部分几何尺寸的计算公式,对齿廓外轮廓进行分段。提出了一种在小范围内确定齿轮中心的方法,并且实现了直齿圆柱齿轮外部轮廓的分段,在视觉测量中小模数齿轮上有一定借鉴意义。     

一种齿轮渐开线齿廓精确求解及其参数化建模方法

根据渐开线生成的基本原理,提出了一种以半径为增量参数的渐开线精确求解方法,该方法可避免求解复杂的压力角超越方程.利用该方法,通过对SolidWorks的API编程,实现了精确齿形的渐开线齿轮参数化三维建模和二维工程图的自动生成,为渐开线齿轮齿廓精确造型和齿轮参数化、系列化设计提供了一种新的方法.     

双面加工的弧齿圆柱齿轮精确参数化设计与装配仿真

弧齿圆柱齿轮是一种新型齿轮,其齿形复杂,齿线呈弯曲的弧线,建模困难。分析其双面加工的过程和齿形展成原理,利用Pro/E的全相关特性,模仿其切削成形过程,实现弧齿圆柱齿轮的全参数化设计和精确建模,并对生成的配对齿轮进行装配与运动仿真分析。     

基于UG的曲线齿圆柱齿轮的特征建模

曲线齿圆柱齿轮传动作为一种新型的齿轮传动,不仅继承了传统齿轮的优点,还有传动平稳、接触线长、加工工艺简单等优点。根据曲线齿圆柱齿轮的加工原理,提出基于齿轮齿条啮合原理的曲线齿圆柱齿轮的特征建模方法;同时以二次开发工具UG/Open GRIP编写程序实现曲线齿圆柱齿轮的仿真加工。建立的曲线齿圆柱齿轮的实体模型,可以进行曲线齿圆柱齿轮的模拟装配、干涉检验、运动仿真和有限元强度分析,为曲线齿圆柱齿轮的优化设计、制造和分析检验打下基础。     

基于渐开螺旋面形成原理的渐开线齿轮造型

文章针对渐开线齿轮的造型问题,分析了渐开线与渐开线螺旋面的关系,采用渐开线螺旋面形成原理,提出了一种新的渐开线齿轮造型的方法。根据渐开线螺旋面的基本性质——渐开线螺旋面与端截面相交所得的平面曲线为渐开线。直接利用渐开线螺旋面的端截面作为齿轮渐开线部分的齿廓,结合齿轮基本参数实现全部齿廓的绘制,通过拉伸或扫描即可完成渐开线齿轮的造型。文章以直齿圆柱齿轮造型为例,详细论述了利用渐开线螺旋面与渐开线的关系来完成直齿圆柱齿轮造型的方法和技巧,实现了渐开线齿轮的精确建模。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.