基于AMESim的脐带缆液压传输特性及等效方法仿真研究

分析脐带缆液压管线传输特性,提出等效方法。应用AMESim建立脐带缆液压管线液压仿真系统,进行仿真模拟,分析仿真结果,研究脐带缆的液压传输特性,并与相似性原理下脐带缆液压传输特性参数进行相对分析,确定脐带缆液压特性参数液阻、液容、液感在液压系统中的表现形式。根据分析结果,确定脐带缆液压传输特性的等效模型的形式,确定液阻、液容、液感的具体等方式,应用AMESim仿真分析了等效方法的等效性,确定了一种脐带缆液压管线的等效模型搭建形式。仿真结果可做为脐带缆液压等效装置搭建的理论参考。     

基于AMESim水下液压控制系统仿真分析

复合电液控制是目前深水油气田开发应用较多的控制方式。对水下液压控制系统进行分析,对主要的液压参数如操作压力,HPU蓄能器、水下蓄能器容积进行计算;依据南海某油气田工程实际,应用AMESim建立水下电液复合控制系统充压仿真模型,仿真模拟不同脐带缆管径对系统充压和ESD的影响,并利用AMESim仿真软件对南海某油田液压控制系统典型工况进行建模和动态仿真。仿真结果表明,该液压系统的各项性能指标均满足相应标准规范和工程的要求。该仿真研究为脐带缆管径选择提供参考,对水下液压控制系统的关键元部件选择分析有很好的参考和指导作用。     

基于响应面法的长管道水下液压系统优化设计

针对海上钻井平台上带长管道的水下液压系统进行研究,建立该系统的简化数学模型,对系统的时域响应进行分析。应用AMESim仿真软件对该系统进行建模并分析其动态特性,得出不同管长、管径、油液黏度以及弹性模量条件下的系统响应曲线;分析蓄能器的位置对系统动态特性的影响。利用基于响应面法的Box-Behnken试验设计方法分析各因素对系统动态响应时间的影响程度,得出各因素与响应时间的数学模型。对系统进行参数优化设计,得到最佳的管长、管径、油液黏度、弹性模量及蓄能器位置的优化设计方案。优化结果与原设计对比后发现,优化设计的响应时间仅为原模型动态响应时间的34.9%,极大提高了系统的响应时间,为水下液压系统带长管道系统设计提供了参考。     

水下拖曳升沉补偿负载模拟加载系统的设计

提出并设计了一种水下拖曳升沉补偿负载模拟加载系统,通过张力模拟信号发生器对水下拖曳升沉补偿系统的负载理论值进行实时计算,采用电液比例溢流阀控制液压马达驱动加载液压绞车实现对升沉补偿系统的加载.应用Simulink工具建立了液压加载系统的仿真模型,并对其性能进行了仿真研究.仿真结果表明,该负载模拟加载系统能够对水下拖曳升沉补偿系统的负载进行准确模拟.     

水下生产配套装置线性覆盖工具液压系统设计与仿真

为了解决水下生产配套装置线性覆盖工具输出的液压推力过小不能完全打开水下采油树阀门的问题,根据水下生产配套装置线性覆盖工具的运动特点,设计一套液压系统。通过Simulink/SimHydraulics模块构建线性覆盖工具中主活塞缸液压系统仿真模型,并对该系统进行仿真研究。仿真结果表明:线性覆盖工具主活塞缸在打开水下采油树阀门的工作状态下活塞杆运动平稳、无杆腔压力稳定,能够完全打开采油树阀门。通过与现场试验结果对比分析,该液压系统的各项仿真数据与实验结果基本吻合,证明了该液压系统具有合理性与可行性,同时也说明了该液压系统符合设计要求。     

车辆制动能量回收模拟系统设计与仿真

目前国内液压节能汽车试验平台结构复杂,管路繁多,液压泵/马达、飞轮等的动态参数不确定,无法满足多种工况下的实验配合问题。新型车辆制动能量回收模拟系统,使用电液比例控制系统代替传统的液压泵/马达,可实现能量回收过程多种复杂工况的动态模拟。设计车辆制动能量回收模拟系统,运用MATLAB/Simulink软件,建立了车辆制动能量回收模拟系统的仿真模型,通过仿真得到了该模拟系统在充、放液过程中的动态特性,并设计了试验台架,为后续车辆制动能量回收系统的实验研究提供了平台。     

基于AMESim的防突钻机液压系统动态仿真分析

分析全液压防突钻机回转液压系统的工作原理,利用AMESim软件建立其仿真模型,并进行动态仿真分析,得到了不同负载下马达进口压力变化曲线,并通过现场模拟试验验证了仿真结果的正确性;对影响系统动态特性的因素进行分析,得到不同等效黏性阻尼系数的情况下马达输出转速和进口压力的响应曲线。试验和仿真结果表明,该回转液压系统具有良好的动态特性以及很强的负载适应性。     

水下控制模块液压系统控制性能研究

为研究水下2 000 m控制模块SCM液压系统在不同工况下的控制性能,建立水下阀门执行器开启和关闭过程动力学模型、长软管模型、电液换向阀模型,对相关参数进行计算,利用AMESim软件对整个液压系统进行仿真,得出执行器、液压动力源和水下控制模块之间的系统压力、回油压差和执行器活塞杆位移的动态性能关系,同时在SCM测试装置上利用SCM液压系统开启一个和多个阀门执行器,得到开启执行器供油压降对液压系统执行性能的影响。结果表明:该液压系统能对12路油路进行控制,水下紧急关断8个执行器比单个执行器延长17 s;液压系统完全开启和关闭单个执行器的每个动作在10 s以内;开启的油路越多,新开启油路压降就会越小,响应速度越快。     

某水下航行器舵机液压伺服系统建模仿真

以某水下航行器舵机液压伺服系统为研究对象,建立舵机液压系统的数学模型.针对实际工况,基于AMESim仿真软件,对该液压伺服系统的动态响应特性、抗干扰能力进行仿真分析.仿真结果表明该系统具有良好的动态响应特性和较好的抗干扰能力,对实际工程应用具有一定的指导意义.     

液压挖掘机可回收潜能研究

为最大限度地挖掘液压挖掘机的可回收潜能,以某公司8 t级液压挖掘机为研究对象,开展了液压挖掘机各执行机构可回收能量大小研究。基于液压挖掘机各执行机构工作原理,建立了挖掘机机械结构及可回收能量液压系统模型。以液压挖掘机国际通用标准工作循环,仿真分析了挖掘机各执行机构可回收能量大小,并通过试验验证了数学模型及仿真结果的正确性。研究结果表明:标准工作循环,液压挖掘机动臂、斗杆及回转机构可回收能量分别为33.21、11.76和18.74 k J,为液压挖掘机能量回收系统的开发提供了理论基础。     

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.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

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.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

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).     

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.