基于Pro/E和ADAMS的圆柱分度机构参数化建模及仿真

利用空间包络曲面的共轭原理建立了圆柱分度凸轮的数学模型,使用 Pro ／E 三维软件的参数化建模功能对特定的圆柱分度凸轮进行设计和精确建模,建立了圆柱分度凸轮机构虚拟样机模型,使用 ADAMS 软件对其进行动力学和运动学仿真分析。仿真结果表明：该机构模型建立的正确性,得到了具有实际应用价值的结论,对圆柱分度凸轮机构的设计、加工、安装起到了一定的指导作用。     

基于Pro/E和ADAMS的圆柱分度机构参数化建模及仿真（英文）

利用空间包络曲面的共轭原理建立了圆柱分度凸轮的数学模型,使用Pro/E三维软件的参数化建模功能对特定的圆柱分度凸轮进行设计和精确建模,建立了圆柱分度凸轮机构虚拟样机模型,使用ADAMS软件对其进行动力学和运动学仿真分析。仿真结果表明:该机构模型建立的正确性,得到了具有实际应用价值的结论,对圆柱分度凸轮机构的设计、加工、安装起到了一定的指导作用。     

钢球滚子弧面分度凸轮机构的三维建模及运动仿真

介绍钢球滚子弧面分度凸轮机构三维模型的建立和运动仿真过程.根据包络蜗杆分度机构啮合原理得到弧面凸轮廓面方程,并求得钢球滚子中心轨迹点.实现钢球滚子弧面分度凸轮机构组件三维几何模型的建立和装配,并对钢球滚子弧面分度凸轮机构进行运动仿真.分别用简谐运动曲线和修正正弦曲线进行对比验证,结果表明:建立的三维模型是正确的和可行的,修正正弦曲线能够使弧面分度凸轮的运动更加平稳.     

分度凸轮机构的三维实体显示与运动仿真

为了将复杂的凸轮机构可视化,实时地模拟分度凸轮机构的真实运动状态,建立了分度凸轮机构的轮廓曲面方程,运用OpenGL技术,对其进行运动仿真.在此基础上,该运动仿真系统可以方便的实现分度凸轮机构的三维参数化结构设计.     

一种新型行星式分度凸轮机构的研究

在分析间歇传动机构创新研究成果的基础上,基于行星轮系齿轮传动的原理,从高速、高分度精度出发,提出了一种新型分度凸轮传动机构。该分度机构将行星轮系的一个中心轮设计为凸轮,推动行星轮和系杆实现分度输出运动。本文应用张量法建立了该类机构凸轮的廓线方程,并对该类机构的结构与设计参数进行了系统的分析。最后,通过编程给出了该类分度机构的计算机仿真实例。该类分度机构具有结构紧凑、输入输出同轴等特点,补充和丰富了平行轴式间歇传动机构的产品类型,可成为间歇分度和步进输送机构的新型产品。     

包装机空间圆柱凸轮的设计及数控加工工艺研究

结合空间圆柱凸轮的结构、工作及使用特性,对包装机空间圆柱凸轮机构进行设计,确定了凸轮的运动规律,运用UG NX8.5进行三维数字建模,并进行动力学分析,验证了圆柱凸轮设计和三维建模的正确性。为了提高加工效率和零件精度,减少自动生成数控程序的缺陷,运用参考线加工策略对空间圆柱凸轮加工工艺进行研究,建模时设计控制曲线,利用Power Mill软件进行CAM编程,改进了加工工艺,提高了编程效率,实现了空间凸轮的数控加工,对工程中同类零件的设计和数控加工具有一定的参考价值。     

圆柱分度凸轮的精确建模与数控编程

应用UG的二次开发工具UG/Grip开发了圆柱分度凸轮的建模系统,实现了圆柱分度凸轮的三维数字化精确建模,再利用UG CAM模块的可变轴曲面轮廓铣对凸轮沟槽进行数控编程与加工,提高了圆柱分度凸轮数控加工的质量和效率。     

盘式刀库及自动换刀装置可靠性评价

圆盘式刀库及自动换刀装置是加工中心的重要功能部件,也是加工中心故障部位的薄弱环节,其可靠性水平直接关系到主机的性能.目前圆盘式刀库及自动换刀装置的可靠性还没有适当的标准.鉴于此,在对国内外数控机床及其关键功能部件可靠性评价研究进行归纳分析的基础上,本文通过平均故障间隔换刀次数MTCNBF及平均修复时间MTTR指标对YP系列圆盘式刀库及自动换刀装置进行了可靠性评价.并基于可靠性加速试验数据对圆盘式刀库及自动换刀装置的故障模式、故障原因进行了分析,得到了圆盘式刀库及自动换刀装置最容易发生故障的部位、主要故障模式,可为刀库及自动换刀装置的改进设计提供依据.     

弧面分度凸轮机构参数化设计与仿真

以弧面分度凸轮机构为研究对象，基于VC＋＋面向对象的方法及Pro／ENGINEER二次开发技术，建立了弧面分度凸轮参数化设计系统，该系统给出了界面友好的参数输入对话框，能够完成机构参数的自动综合和凸轮轮廓的自动生成，具有直观性、易于操作和调整，并在Pro／ENGINEER环境下进行装配、仿真与干涉检测，验证了设计的合理性。     

花键冷敲成形设备分度机构分析与优化

对花键冷敲成形设备分度机构进行了分析。通过对传统的直线槽轮机构进行运动学和动力学分析,发现直线槽轮分度机构在拨销进入和离开轮槽的时候发生柔性冲击,引起了分度机构的振动。在此基础上,设计了两种减小冲击的分度机构:新型曲线槽轮机构及弧面凸轮分度机构。对这两种分度机构进行了设计计算,建立了几何模型,并进行了运动学及动力学特性分析。结果表明:改进之后的分度机构可以减少冲击,分度精确,运行平稳。     

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.