液压马达加载测试装置的设计研究

本文设计了一套液压马达的加载测试装置，该装置能够按照实际工况对液压马达进行性能测试，由于系统采用了比例控制技术和信号自动采集系统，从而提高了系统的测试自动化程度和测试精度；同时有效解决了液压马达的低速加载稳定性问题。     

电液舵系统性能综合测试系统的研究

针对某舰船电液舵系统的工作特点。设计了高精度全自动综合测试系统。采用电液加载和弹簧加载两种加载方式,并采用交流伺服电机作为手轮驱动机构。实现了舵系统4路舵机的静动态性能同步测试;测试计算机可靠性高,界面友好美观,测试功能强大,具有故障诊断分析功能。测试结果表明：舵系统性能综合测试系统设计科学合理,技术水平先进,具有很高的测试精度和自动化程度。     

电流伺服阀性能测试试验台的改造

介绍了电液伺服阀性能测试试验台的改造方案，改造后的试验台既能进行静态特性测试又能进行动态特性测试，系统采用比例节流阀加载方法以及基于虚拟仪器的CAT技术，实现了测试过程的自动化。     

电流伺服激振台及其极限工作范围的研究

本文介绍了电液伺服激振台的工作原理，着重讨论了在正弦激励信号下电液伺服加载系统极限工作范围的确定方法，及其应用实例，它对激振加载实验的设计，调试及测试结果分析都具有一定意义。     

摩擦提升试验平台的电液加载系统设计与测试

目前大部分提升机试验台主要针对研究元部件特性而单独设计,而没有体现有机整体。在综合分析现有各种加载方法的基础上,设计摩擦提升试验平台的电液加载系统,介绍该系统的构成和工作原理,并进行加载实验。该系统最大的特点是动力来源于摩擦轮且作用于摩擦轮,在达到提升扭矩加载要求的同时,实现了能量回收。实验测试结果验证了所设计的电液加载系统的有效性。     

舵机电动伺服加载控制系统的设计与研究

针对电动舵机加载要求,设计了以交流伺服电机做加载设备的舵机电动伺服加载实验台。此加载装置用于测试电动舵机在近似于真实工作环境下承受各种载荷时,电动舵机可能出现的状况。给出电动加载系统的整体结构及其工作原理,介绍所采用的抗电磁干扰措施。建立电机和力矩传感器的数学模型,给出加载实验台的静、动态性能测试结果。实验结果证实加载试验台可以满足设计要求。     

电动力加载台测控系统建模与设计

设计了一种新型力加载结构,通过滚珠丝杠副实现力矩到力的转化,完成对被测机构的力加载。给出了加载台的结构组成及系统工作原理,并建立了系统的数学模型。采用了PID控制和基于结构不变性原理的复合前馈控制策略对系统进行了设计,仿真结果表明:系统可完全满足测试指标要求。该系统相比传统力加载台,具有转动惯量低、加载电机功率小等优点,并具有一定的工程参考价值。     

直线运动机构电动加载测试系统建模及仿真分析

设计了一种新的直线运动机构电动加载测试结构,该结构通过滚珠丝杆副将电机的旋运动转换为直线运动,可以直接对直线运动机构进行力加载。分析建立了该系统数学模型并给出了可靠的控制方程。系统采用了基于结构不变性原理进行前馈补偿和通过PID进行反馈控制的复合加载控制策略,对因跟随直线机构运动而产生的多余力矩进行抑制。经仿真验证抑制效果明显,完全符合低频情况下的加载测试要求,具有较高的工程参考价值。     

舵机动刚度加载系统设计与分析

动刚度是舵机不可忽视的一项动态性能,加载系统的性能直接影响动刚度的测试结果。分析系统的原理结构,从静压支承伺服作动器的计算设计、伺服阀的选型、回油系统与安全保护措施的设计等方面对加载系统进行了全面设计。该系统已经投入使用,性能表现良好。     

车床静刚度计算机测试系统研制

在分析了车床的结构特点和车削工艺系统的受力情况和借鉴传统车床静刚度仪优点的基础上，研制了一套基于计算机控制的车床静刚度测试系统。系统由计算机作为信号检测、数据处理和控制核心，并配以精密位移传感器、压力传感器和步进电机及其驱动器等。实现了自动加载、卸载，采样，数据处理，直接绘制、显示和打印刚度曲线等功能。系统的成功研制为车床静刚度的测试提供了一种先进手段。实测结果表明，该系统具有自动化程度高、测试效率高、精度高、可靠性高、测试性能稳定的优点。     

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。