基于分布式仿真的液压能源系统效能评估方法研究

飞机液压能源系统是支持飞机主飞控系统、高升力系统以及起落架等关键系统正常工作的核心动力来源,其系统效能是飞机液压能源系统的一个重要设计指标。针对目前飞机液压能源系统的效能分析缺乏完善且有效的方法,设计一种基于分布式仿真的效能分析方法。结合系统工作原理,运用AMESim建立液压能源系统分布式仿真模型,在考虑全飞行过程液压能源系统加载负载工作情况下,对液压能源系统效能与关键指标的关系进行研究,建立了三层两级效能评估指标体系,并验证了指标体系的有效性。运用熵权法对效能指标进行相对权重分析,采用扩展贝叶斯融合算法对飞机全飞行过程中的液压能源系统负载在环的部件级效能和系统综合效能进行了研究。最后以某航班真实飞行任务数据为例,验证了效能分析方法的正确性。     

基于ADAMS与EASY5的40 kN液压起重机联合仿真

以液压起重机为研究对象,在UG软件中完成结构的三维建模,导入动力学仿真软件ADAMS中建立液压起重机的虚拟样机模型,利用EASY5软件建立起重机的液压系统模型,通过设计软件数据接口实现了液压起重机的机械/液压联合仿真。结果表明:虚拟样机模型与液压系统模型实现了无缝联接,验证了联合仿真方法的有效性与实用性。     

基于Easy5和Adams的液压减振器联合仿真

为了得到系统的动态特性,常常需要借助软件建立机械系统的数字化模型,在要求的工况下进行计算,以指导系统的设计。以一个液压减振器为例,采用MSC.Adams和MSC.Easy5进行联合仿真,实现对机械系统的动力学分析。计算结果表明:联合仿真模型与原始模型计算结果基本吻合。同时在联合仿真模型中,通过对阻尼器内部结构的分析,得到了更接近实际模型的数学模型,使仿真计算精度提高,为进一步分析液压减振器的物理结构与工作特性的关系提供了研究工具。     

基于AMESim与ADAMS的轮式装载机联合仿真

轮式装载机包含紧密耦合的液压系统和执行机构,很难在单一的软件平台中准确实现其动力学仿真。建立了装载机AMESim液压系统模型及ADAMS虚拟样机模型,利用上述两个软件进行联合仿真,使液压系统和机械系统可以实时交互作用。最后,将联合仿真结果与仅使用ADAMS进行的动力学仿真结果进行了比较,证明联合仿真结果是合理的。     

民机2H/2E能源系统正常工况下液压压力可达性分析

出于对高功重比的追求,民机液压能源系统压力流量裕度较小,但由于用户多、系统复杂,如果压力流量裕度过小,在有些飞行剖面下可能会产生流量压力纷争而导致系统压力不可达,因此进行压力可达性分析是民机液压能源系统设计的首要工作。以民机34.47 MPa(5 000 psi)压力体制2H/2E能源系统架构的一套液压能源系统为对象,在分析其工作原理及压力损失机制的基础上,在AMESim软件中搭建相关元件的标准模型和超级模型,进而建立该套液压能源系统的仿真分析模型,得到-8℃环境温度下飞机液压能源系统的压力可达性规律。目前国产民机34.47 MPa(5 000 psi)压力体制2H/2E能源系统架构及其液压系统研究处于起步阶段,相关研究成果将为宽体飞机研制提供支持,同时对我国大型民机液压能源系统设计、评估及优化提供参考。     

装载机偏载工况工作过程联合仿真与试验

为了分析装载机在偏载工作过程中的能量消耗情况,首先使用Pro/E软件建立了装载机工作装置的三维模型,将其导入SimulationX仿真软件中建立了装载机的动力学模型,同时使用该仿真软件建立了装载机工作装置液压系统模型,进一步建立了装载机联合仿真模型。然后对工作过程各个工作部件能量消耗情况进行了仿真和试验研究,通过比较仿真与试验结果,验证了所建立装载机工作装置机液联合仿真模型的准确性。结果表明：偏载工况下,多路阀的能量损失占52%;多路阀在一个工作循环中消耗能量最大,主要是中位卸荷损失。该研究为装载机液压控制系统节能设计提供了参考。     

基于AMESim与ADAMS联合仿真技术的减摇鳍液压系统仿真研究

为了对机、电、液一体化减摇鳍液压系统准确仿真,提出了基于AMESim与ADAMS联合仿真技术的建模与仿真方法,运用ADAMS软件建立机械系统多体动力学模型,采用AMESim软件对液压系统与控制系统建模,完成较准确的系统模型,并分析了减摇鳍液压系统的动态特性,将获得的数据与实测数据进行比较,证明联合仿真与传统仿真方式相比结果更准确.     

基于AMESim与ADAMS的超静定液压支架液压系统联合仿真

为了分析超静定液压支架的承载能力,通过机械结构和液压系统两个方面进行研究,运用AMESim和ADAMS机液联合仿真的方法。在ADAMS中对液压支架进行动力学建模,并导出模块接口,然后在AMESim中建立液压支架的联合仿真模型。对液压支架进行了多种工况的仿真分析。分析结果表明:超静定液压支架不论从机械结构和液压系统方面都能抵抗不同条件下的工作载荷,满足煤矿下的使用要求。     

装载机偏载工况工作过程联合仿真与试验（英文）

为了分析装载机在偏载工作过程中的能量消耗情况,首先使用Pro/E软件建立了装载机工作装置的三维模型,将其导入Simulation X仿真软件中建立了装载机的动力学模型,同时使用该仿真软件建立了装载机工作装置液压系统模型,进一步建立了装载机联合仿真模型。然后对工作过程各个工作部件能量消耗情况进行了仿真和试验研究,通过比较仿真与试验结果,验证了所建立装载机工作装置机液联合仿真模型的准确性。结果表明:偏载工况下,多路阀的能量损失占52%;多路阀在一个工作循环中消耗能量最大,主要是中位卸荷损失。该研究为装载机液压控制系统节能设计提供了参考。     

基于EASY5的某型飞机武器舱门收放过程仿真

分析某型飞机武器舱门液压系统原理,使用液压仿真软件MSC.EASY5建立武器舱门液压系统仿真模型并进行飞机武器舱门收放过程仿真.仿真结果与理论分析结果基本相符,表明该型飞机武器舱门液压系统能提供操纵武器舱门所需的足够的压力和流量,为该型飞机武器舱门液压系统的试验和使用提供参考.     

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.     

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.     

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.