航空航天作动系统和元件先进技术国际交流会2016（R3ASC16）介绍

航空航天作动系统和元件先进技术国际交流会,为世界各国作动系统和元件研究团体的设计研发人员提供了交流平台,该会议探讨了当前航空航天作动器技术发展现状和发展趋势,促进先进作动技术的快速发展。本文主要从作动器建模仿真技术、驱动控制技术、健康管理技术、元件设计技术以及标准化进展等方面来提升航空航天作动器的轻量化、高效能、高可靠性、高安全性,同时提升易维护性,降低全生命周期成本。我国在航空航天作动器相关技术方面相对国外存在较大的追赶空间,这次会议展示了世界范围内航空航天作动器的最新技术和产品成果,希望能为国内从事相关工作的研究者提供一定的启发。     

EHA作动器建模与仿真分析

电静液作动器(EHA)能够实现故障安全,不存在机械卡死等,在大功率的场合功重比优势明显,因此可应用到飞机主舵面的伺服控制系统中。介绍EHA的组成、工作原理和功能组件的作用,详细推导了EHA伺服作动系统三环闭环控制情况下的数学模型,并在此基础上进行频域分析,设计伺服回路参数,在AMESim仿真平台上搭建了EHA伺服作动系统的仿真模型。利用推导的EHA数学建模方法可实现EHA作动伺服回路参数的设计,同时还可实现EHA作动器关键参数敏感度分析;利用给出的仿真分析方法可在EHA设计初期验证EHA伺服作动系统的性能,为作动器的实物设计提供理论基础。     

机载一体化作动系统的发展趋势

本文分析了飞机上传统液压作动系统的缺点，归纳了采用一体化电动作动器的优点，论述了发展功率电传作动器的必要性。接着概述了近来国内外机载一体化电动作动器的发展状况，最后比较了两种一体化作动系统的优劣并指出一体化作动系统的最终发展方向。     

电静液作动器的建模仿真与试验研究

电静液作动集成技术是航空界未来航空器发展的五大关键技术之一。简述了电静液作动器EHA国内外发展动态,对定排量变转速型电静液作动器进行了原理分析、建模和仿真、试验验证。结果表明：所设计的电静液作动器满足技术要求,达到了预期目标,能实现高性能控制,但其某些方面还有待进一步的优化。仿真分析和试验结果为EHA的系统设计和工程优化提供参考。     

一种新型电液作动系统

本文提出了一种新型的电液作动系统 ,即电动静液作动器EHA。针对具体的电动静液作动器 ,用EASY5软件对系统进行了仿真分析 ,仿真结果表明所设计的系统具有良好的动态性能 ,并达到给定的性能指标     

基于直驱式容积控制作动器的倾摆系统研究

针对摆式列车倾摆系统要求,依据直驱式容积控制电液伺服技术完成了作动器结构设计,建立基于AMESim系统的仿真模型.运用ADAMS动力学软件建立摆式列车倾摆机构的动力学模型,并与AMESim软件实现了对倾摆作动系统的联合仿真.仿真结果表明,采用直驱式容积控制电液伺服作动器的倾摆作动系统性能良好,达到了预定的性能指标,能满足摆式列车的要求.     

一种新型电流作动系统

本文提出了一种新型的电液作动系统，即电动静液作动器EHA。针对具体的电动静液作动器，用EASY5软件对系统进行了仿真分析，仿真结果表明所设计的系统具有良好的动态性能，并达到给定的性能指标。     

紧凑型灵巧作动器的伺服控制

与有人机相比,无人机作动系统要求在更小的空间内实现相同功能,这就要求作动器更加灵巧、紧凑。提出一种新型的紧凑型灵巧作动器,该作动器采用永磁同步电机驱动2个柱塞协同工作,实现吸排油;通过方向阀实现油液的配流,将上述实现液压泵功能的结构全部集成在壳体内,减小了作动器的体积。本文还设计了该作动器的伺服控制回路,详细阐述了如何选取速度、电流环的PI参数。通过在AMESim中搭建仿真模型驱动质量负载,证明该作动器响应速度快,动态性能好,带载能力强。     

货舱门作动系统用旋转作动器设计改进

对货舱门作动系统用旋转作动器因销轴、行星轮内孔、行星架磨损而失效的现象,从失效形式、失效原因、材质选用、结构等方面进行全面分析,有针对性地对产品进行设计改进。主要改进要点为:改进销轴材料和热处理工艺,行星轮内孔表面精度和热处理工艺,提高销轴和行星轮内孔的硬度和耐磨性;改进行星架结构,对改进前后行星架结构进行有限元分析,使其静强度提高了1.5倍以上。通过改进,解决了旋转作动器失效问题,试验证明改进措施正确有效。     

作动器试验故障分析及改进

作动器是飞机飞行控制系统的关键部件,试验是验证作动器是否满足设计要求的可靠手段.从某作动器试验故障入手,对作动器的设计、制造、试验环节进行了全流程分析,定位了故障原因,并研究故障机制,提出了改进措施.为类似产品的故障分析提供了一套可借鉴的方法,所采用的强度分析方法为类似产品的设计、验证提供了参考.     

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。