残疾人举重液压伺服保护装置设计

设计一种残疾人举重保护装置,该装置由导轨、液压跟随单元、液压托举单元等三部分组成,主要依据液压伺服原理工作。阐述了该装置的技术方案,并对装置的核心结构做了选型设计。     

铸管厂铸铁机专用液压倾翻装置

传统铸管行业内铸铁机采用铸造起重机浇铸,不仅影响铸管生产,成为瓶颈,也降低了铸造起重机的寿命和增加了维修成本,同时飞溅及铁损也比较大,生产成本增加而且安全性较差。因此结合实际生产工艺及布局和铸铁机的生产能力,对现有的倾翻装置的形式进行研究,从成本、安全、操作、维护等方面分析其优劣,最终采用液压倾翻装置。本文详细介绍了该液压倾翻装置的结构组成及各功能单元,给出了装置相关的技术参数。设计时主要对该装置的安全性、可靠性及操作方便性进行重点研究,特别是安全钩,摇架以及液压系统等方面。该倾翻装置投入使用后,彻底地解放了铸造起重机,减少了铁损,大大提高了浇铸安全性,创造了较好的经济效益,为相关的研究设计提供一定的参考价值。     

海洋石油平台钢桩内水泥清理装置研究及试验

为解决弃置海洋石油平台导管架钢桩内有水泥灌注的问题,研究一种适用于水下作业的导管架钢桩内水泥清理装置。对比分析目前各种水泥破碎方法的优点、缺点及应用情况,结合水下作业环境,得出基于高压水射流原理的导管架钢桩内水泥清理方法可行。设计包括给水泵、高压水泵、合流块、液压动力单元、液压控制台、角度显示装置、供气动力单元和高压水喷头的海洋石油平台钢桩内水泥清理装置。结果表明：该装置可有效地解决海洋石油平台弃置过程中导管架钢桩内有水泥的工程问题。     

液压控制在路面铣刨机中的应用

针对一款应用在高速铁路建设的路面铣刨机进行液压控制装置设计。在该装置中,通过一个液压泵分别与铣刨转子液压控制机构、行走液压控制机构和支承液压控制机构连接,使该装置操作响应速度快、结构简单、切削深度稳定、操作方便,大幅度减少了维修量,为高铁的建设进度提供了保障。     

采煤机模拟实验装置液压系统设计

分析采煤机模拟实验装置的组成及工作原理,设计该装置的调高与牵引液压系统回路,对液压系统的主要元件包括液压缸、比例方向阀和液压泵进行了计算选型,对类似液压系统的设计及选型有较大的参考价值。     

船用调距桨液压系统可靠性预计和分析

调距桨作为广泛使用的舰船主推进装置,其动力源液压系统结构复杂且所处环境恶劣,为了更好地实现调距桨全寿命周期可靠运行,对该液压系统进行了可靠性研究。在详细描述主控制液压系统功能原理的基础上,建立了复杂串并联可靠性模型,结合故障率预计法、评分预计法及元器件计数法进行了从单元到系统的可靠性预计,并采用定量危害性矩阵分析方法对代表性单元实施了着重于危害度分析的FMECA,得出了系统及各单元的故障率和可靠度的时间曲线,以及主要单元及其故障模式的危害度值。结果表明:这种综合的预计方法较适用于部分非电子零部件数据难以收集的系统,而顺序阀、梭阀、溢流阀等单元故障对系统可靠度影响较大,为系统可靠性设计提供了理论参考及改进方向。     

飞行影院升降平台液压控制系统单元的设计

安全可靠的液压控制系统是飞行影院升降平台装置必不可少的部分。通过集成化、模块化设计,开发一个技术水平含量高、能够满足飞行影院升降平台平稳快速升降的液压控制单元,满足飞行影院升降平台液压系统高效率低能耗、高可靠性等要求,符合我国飞行影院行业的需求。     

液压风力发电系统设计及仿真

主要介绍了液压传动与控制技术在风力发电装置的应用,并对风力发电装置液压传动系统进行了设计计算。利用AMESim对风力发电装置液压系统进行建模和动态仿真,结果表明:该液压发电装置在原理上是可行的,同时可以实现不同风速输入和马达速度的稳定输出,从而有利于提高发电机电压的稳定性,并且该系统的油箱、马达、发电机及控制装置安装在地面,降低了塔架承受的重量,也节约了制造成本和维护成本。     

一种槽式太阳能集热装置液压系统的设计与仿真

太阳能集热装置是太阳能设备的重要组成部分。液压系统由于运行平稳、适应能力强,在太阳能集热装置中有着广泛的应用。通过分析太阳的运行规律、集热装置的结构及工作过程,设计了一种针对集热装置的液压控制系统,并在AMESim仿真软件中建模进行仿真分析,验证其可行性,从理论上使该太阳能集热装置液压系统的设计得以实现,为下一步的生产应用打下基础。     

软质管线收卷机头展收机构的动力学研究

基于达朗贝尔原理结合牛顿欧拉法和有限单元的方法建立机头展收机构的动力学模型,牛顿欧拉法为刚体力学模型,有限单元法属于弹性体力学模型,牛顿欧拉法计算的轴力最大值为137 k N,而有限单元法的轴力极值达到720 k N。计算结果表明:有限单元法计算的液压变幅构件轴力曲线变化平稳,但计算量较大;牛顿欧拉法计算量小,但容易产生轴力曲线波动失真现象。牛顿欧拉法和有限单元法在机构设计前期为确定液压变幅构件的轴力提供科学凭据,有助于设计出性能优越的机头展收机构液压装置。     

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).     

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.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

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.