液压电梯液压系统及现场检测方法研究

液压电梯相比曳引式电梯具有高的功率质量比和良好的可靠性,适合中低层建筑。但是液压电梯主控阀结构较复杂,系统安装、调试及日常维修保养的技术要求较高,某种程度上影响其广泛应用。介绍现有的几种典型的液压电梯的液压系统工作原理、主控阀结构及发展趋势,同时分析其定期检验的液压主控阀压力设定、流量特性、防沉降功能等参数的检测方法和评判准则。该研究有利于技术人员加深对液压电梯的认识,以促进其推广和应用。     

阀控缸型式液压电梯的振动模态分析

所设计的液压电梯采用直顶方式,以阀控缸型式液压电梯作为研究对象,构建了其物理模型,建立了基于柱塞缸与轿厢架(m_1)、轿厢与电梯载重(m_2)二自由度的阀控式液压电梯系统动力学方程。在此基础上,讨论了该液压电梯系统的振动固有频率的计算方法。通过仿真实验,着重分析了其油液刚度、轿底橡胶减震垫刚度以及轿厢载重大小的变化对系统固有频率的影响。结果表明:其他条件不变情况下,液压电梯系统的一、二阶固有频率随油液刚度的减小而减小;液压电梯系统的一、二阶固有频率随轿底橡胶减震垫刚度的增大而增大;液压电梯系统的一、二阶固有频率随轿厢载重的增大而减小。     

水下回填犁调整机构液压系统仿真分析

简述了回填犁的组成和功能,对回填犁各部件进行简要描述,分析回填犁调整机构作用和组成。调整机构主要通过液压缸的伸缩来执行前滑靴工作位姿的调整,因此建立了液压系统的原理图,并使两液压缸满足同步工作和回填时的保压;然后通过AMESim软件对液压系统进行建模仿真,通过给定电磁换向阀不同电流,分析了在回填负载加载时液压系统中液压缸的速度、位移、压力以及流量曲线,验证液压系统满足工作要求。     

电梯轿厢上行超速保护装置现状分析与检验要求研究

通过对国内使用的电梯轿厢上行超速保护器的现状进行分析,并根据TSGT7001—2009的《电梯制造与安装安全规范》和TSGT7002—2009的《特种设备检验检测机构核准规则》,就电梯轿厢上行超速保护器的检查要求进行了讨论,并提出了相应的对策和建议。     

新型柱塞式液压保护装置卸载过程的分析

介绍了一种可用于机械压力机的新型液压保护装置,该装置具有先导阀和柱塞结构,能实现行程调节,并能根据具体实际情况准确地控制超载力、能以较小的预压力实现较大的卸荷力,卸荷时间和补油时间短。本文分析了其工作原理,根据液压流体理论建立了卸载过程的数学模型,为进一步进行液压仿真和结构参数设计优化提供了基础。     

变频液压电梯用集成阀

本发明公开了一种变频液压电梯用集成阀。该集成阀连接在驱动变频液压电梯轿厢升降的液压缸和提供压力油源的液压泵之间，是变频液压电梯中液压控制部分的关键，它包括安全阀、安全阀先导调压阀、液控单向阀、两个二位二通电磁换向阀、手动下降阀。其控制对象集中、外观简洁，在满足变频液压电梯正常上下行基本工作需要之外，还体现在电梯下行时的快速截断性，减少油路冲击，在停电或遇故障时，电梯能够迅速停靠。     

摩擦提升机滑动保护装置液压加载系统建模及参数优化研究

针对摩擦提升机滑动保护问题,设计了一种以液压加载系统作为动力源的摩擦提升滑动保护装置,给出了液压加载系统的原理图,并基于AMEsim建立了液压加载系统模型。通过分析得到了不同参数的液压缸、蓄能器和管路等对于液压加载系统性能的影响。结果表明:为提高防滑装置液压加载系统的响应时间,可以增加蓄能器的容积,减小管路的长度,而液压油缸的大小参数应协调活塞杆位移响应速度和输出正压力大小进行优化设计。     

新型防坠落装置中倒置使用液压缓冲器研究

通常垂直升降设备所用的缓冲器大都设置在地面,重物从上向下冲击缓冲器。研究的缓冲器是用在垂直升降防坠落装置中,当垂直升降设备断绳坠落时,触发防坠落装置动作,使其制停在半空中,液压缓冲器在制停过程中起缓冲和能量转换作用。其特点是:垂直升降防坠落装置用液压缓冲器安装在运动物体(如电梯轿厢)上;运动物体从下向上压缩缓冲器;一旦断绳,立刻制停,坠落冲击的初速度小,缓冲器缓冲效果理想。     

分离式霍普金森压杆试验台液压加载系统的研究

为了研究有压情况下材料在冲击载荷下的力学行为,研制一种在一般分离式霍普金森压杆(SHPB)装置基础上施加两自由度负载的新型SHPB试验台液压加载系统。研究试件机械加载方式,提出密封粉末加载方法,并根据要求设计液压比例控制系统作为加载系统;由压力传感器、位移传感器和数据采集卡等与上位机构成液压加载控制系统,对液压缸压力进行实时监控;用Simulink软件对控制系统进行仿真。仿真结果表明,该系统可以实现对试件的恒定压力加载。     

压力机用液压式超载保护装置设计分析与应用

机械压力机用液压式超载保护装置由以气压为动力源的油压增压泵、高精密超载油压压力卸荷阀和微动开关3部分构成,分为正常运转、超载动作、压力下降3种工作状态。根据工作原理图对3种工作状态进行详细分析讨论,推导出滑块液压垫设定预压力、卸荷阀卸荷压力、卸荷阀最大卸荷量的计算公式,最后列举应用实例进行了验证并提出相关建议。     

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。