一种EHA试验台设计与研究

针对伺服直驱泵控液压系统,研制了一种EHA (电静液作动器)试验台。对试验台数据测试和数据采集系统进行了集成设计,对试验台的组成、技术要求、工作原理以及功能和控制系统进行了设计与研究。该试验台按DDVC系统试验台的要求而设计,能够实现同一试验完成多项测试的目的,具有很好的推广价值。     

液压油缸试验台研制

针对现有液压油缸试验台存在的一些弊端,提出了采用电液比例技术的改造方案,设计了液压系统与试验台控制系统,并论述了系统的配置与工作原理.该系统将计算机控制、检测技术、计算机网络技术与液压控制系统有效地结合起来,可对液压系统各参量进行实时控制,对液压缸各种性能参数进行巡回跟踪检测,使液压缸测试实现了自动化和智能化.     

主驱动密封系统试验台液压系统研究

试验台模拟了盾构机主驱动密封的工作环境,为解决现有的实验装置无法实现使密封圈在左右两腔不同压力点的工作状态,对试验台液压控制系统进行研究。介绍其液压系统的原理组成及其加载装置和动力装置。动力装置通过调节变量泵的排量改变液压马达的转速,以及控制电磁换向阀实现正反转;加载装置通过比例减压阀对油缸输出压力,使波纹管压缩,经由高压液压软管总成对实验容器左右两腔分别加压。并通过AMESIM对以比例减压阀为核心的闭环控制系统进行仿真分析。最终结果表明该控制系统可以满足实验要求。     

基于自适应滑模控制的液压支架试验台同步控制特性分析

为提高液压支架试验台同步控制系统的同步控制性能,提出一种基于模糊理论和滑模控制的自适应滑模控制方法,对液压支架试验台的主从同步控制性能进行研究。分析液压支架试验台同步控制系统工作原理和理论模型;在AMESim-MATLAB环境下建立仿真模型,并对比分析采用模糊PID和自适应滑模控制的系统的同步动态性能。结果表明：采用自适应滑模控制的液压支架试验台同步控制系统的伺服跟踪能力和稳态性能比模糊PID控制的系统更好,验证了自适应滑模控制在液压支架试验台同步控制系统中应用的可行性。     

基于AMESim的转向架综合试验台液压系统设计及仿真

分析跨座式单轨轨道交通公司提供的车辆运行及转向架各试验参数,设计可以模拟车辆实际运行情况的轻轨车辆转向架综合试验台的液压传动及控制系统。根据转向架综合试验测试参数及测试方法搭建液压回路,运用电液比例技术对液路进行精确控制。阐述试验台液压系统各子系统的原理及特点,运用AMES im进行加载回路和调速回路仿真分析,结果表明系统满足转向架试验台工作要求。     

液压元件性能试验台控制系统的研究

液压元件性能试验台是进行液压元件质量检测的必要设备,是液压元件质量监控的保障。介绍液压元件测试试验台的系统组成、原理和特点,采用上位机控制下位机的控制方式对液压元件测试试验台控制系统进行了设计,对多试验台共用液压源的控制方法进行了研究,并提出了实用的方案。     

基于PLC的航空地面液压保障装备负载试验台设计

针对航空地面液压保障装备模拟训练和检测需求,设计一种基于可编程控制器的液压负载试验台,根据其液压系统和电气控制系统的要求,编写梯形图实现对航空地面液压保障装备的液压系统进行密封试验和持续工作时间试验。试验结果表明:该负载试验台工作可靠,满足使用要求。     

某大型装备液压试验台的设计

针对大型装备昂贵、影响力大和生产任务紧等不适合直接对它进行现场试验的问题,设计一种大型装备的液压试验台。介绍其液压系统功能、主要参数、组成、工作原理,对典型元件进行计算与选型,选出合适的液压泵、液压缸和电机,完成其控制系统和监控系统的设计,实现大型装备液压系统在试验台上的性能分析与测试。〖BP（〗结果表明：所设计的大型装备液压试验台可以真实地模拟和再现大型装备液压系统在工业现场的受载特点,对大型装备液压系统的快速排故、提高系统性能有积极作用。     

某型武器装填液压系统的PLC控制研究

介绍某型武器装填液压系统的工作原理,研制以可编程控制器(PLC)为核心的控制系统,对控制系统的硬件结构、控制软件设计以及抗干扰措施等进行详细介绍.实验结果表明该PLC控制系统实现对武器装填液压系统的运动控制,达到预期控制要求.     

摆锤式冲击试验台液压系统的设计

设计一种对被试件抗冲击性和可靠性进行试验的冲击试验台,介绍该冲击试验台液压系统的设计和工作原理;设计使用湿式液压离合器水平自动冲击,防止二次冲击,安全可靠;并应用AMESim对系统动态性能进行仿真分析,结果表明该液压系统能够满足设计要求。     

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.     

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.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。