电液比例溢流阀控制系统动态特性仿真分析

将电液比例溢流阀合理地分解为比例电磁铁和压力控制阀两部分进行分析,研究了其压力输出特性,建立了数学模型,并应用MATLAB进行仿真.仿真过程中提出了合理地确定模型参数的方法,研究了参数对系统输出特性的影响,并为系统的优化提出了建议.     

2D电液比例换向阀用一体式弹性压扭联轴器的ANSYS仿真分析

压扭联轴器是2D电液比例换向阀机构中最为关键的部件。传统直动式电液比例换向阀由于比例电磁铁推力有限,无法实现高压大流量控制,针对此现象,在保证直动式阀结构简单基础上,设计了一体式弹性压扭联轴器,通过其自身的材料和几何变形,将比例电磁铁的直线推力转为阀芯的扭转力矩,应用ANSYS软件进行仿真,结果显示:在比例电磁铁输入直线推力80 N、输入位移为2 mm时,输出扭矩为2 N·m,在无摩擦的情况下实现了力的放大,仿真结果对优化其结构具有一定理论参考价值。     

插装式二维电液伺服阀的动态特性研究

插装式电液伺服阀较传统的电液伺服阀进一步提高了伺服阀的功重比,并具有优良的动态特性。提出一款插装式二维电液伺服阀并重点研究其动态特性。介绍插装式二维电液伺服阀的结构及工作原理。建立插装式二维阀的数学模型并进行仿真分析,尤其对阀芯旋转黏性阻尼系数进行推导。仿真结果表明：开环模式下插装式二维阀的阶跃响应时间为10 ms,幅频宽为40 Hz;闭环模式下阶跃响应时间为4 ms,幅频宽为100 Hz。通过搭建试验平台对插装式二维阀进行动态特性测试,试验结果表明：开环状态下阀的阶跃响应时间为7 ms,幅频宽为38 Hz,闭环状态下两项数据分别为6 ms和117 Hz。试验结果与仿真结果基本吻合,表明插装式二维电液伺服阀具有优良的动态特性。     

湿式电磁铁导磁套的电弧钎焊

一、结构特点及焊接要求湿式电磁铁与干式电磁铁在结构上的主要差异是用非导磁材料制成的隔磁套,代替了原空气间隙式隔磁结构并用焊接方法把内套、挡铁、隔磁圈焊成一个整体即导磁套。由于换向阀两端“O”腔的回油进入电磁铁内部,使衔铁浸于油中工作,故湿式电磁铁具有许多优点:     

一种新型直动式电液伺服阀的研制

基于一种永磁极化式双向比例电磁铁和耐高压电涡流位移传感器,提出一种新型直动式电液伺服阀,进行性能仿真分析,设计出相应的驱动电路并进行实验研究.实验结果与仿真结果吻合,表明提出的电液伺服阀具有良好的静态特性.     

电液单向阀

电液单向阀是一种通电后即允许油液双向流动的单向阀。它是电磁换向阀和液控单向阀的组合(见图)。当电磁铁断电时,换向阀处于常态位,液控单向阀的控制口X不通压力油,其作用与普通单向阀相同,正向流通,反向截止;当电磁铁通电后,换向阀右位工作,液控单向阀控制口通入压力     

基于AMESim的智能综采工作面电液控制系统的

以智能综采工作面电液控制系统为研究对象,介绍该系统的工作原理,分析五柱塞乳化液泵、卸载阀、电液换向阀组的工作原理和结构特点,建立关键元件的数学模型。基于AMESim仿真软件,构建系统关键元件的仿真模型,对不同工况状态下的系统进行仿真,分析卸载阀关键结构参数对系统压力特性的影响。结果表明：仿真模型准确,液压系统性能良好,乳化液泵的流量仿真结果与传统计算方法数值吻合,卸载阀不同阻尼孔参数对系统压力特性影响效果不同。     

一种新型插装式水压电磁换向阀的仿真研究

基于二通插装阀结构,提出了一种新型插装式水压三位四通电磁换向阀的设计方案,并介绍了其工作原理;同时建立了水介质条件下插装式换向阀的AMESim仿真模型,分别分析了不同的阀芯面积比、阀芯阻尼孔直径、先导阀孔直径、阀芯质量以及弹簧刚度等在空载情况下对插装式换向阀动态特性的影响,并基于AMESim仿真分析得到插装式电磁换向阀的最优结构参数及其动态特性曲线。仿真结果表明,具有最优结构参数模型的该电磁换向阀换向迅速、稳定、可靠。     

双推杆电磁铁电磁力仿真

为了提高电液比例阀的响应时间,提出一种新型结构的双推杆电磁铁。根据等效磁路,建立电磁铁的数学模型,采用Ansoft对电磁铁进行有限元分析,用拟合命令对不同电流位移、电磁力响应特性进行曲线拟合,得出施加不同电流密度、电磁铁力移特性的变化规律。运用得出的数据,进行ANSYS Workbench撞击模型仿真,发现推杆撞击挡板后,受力集中在中心和部分边缘地区,长期撞击后,推杆筒很可能发生变形。因管壁较薄,根据云图使用火焰矫正法进行校正。     

电液控制系统用电磁铁的动态特性研究

通过分析电磁铁的使用状况,依据经典设计理论设计出一款电液系统用本质安全型电磁铁,利用MAXWELL对所设计电磁铁进行了动态特性仿真,并搭建实验平台进行了动态特性试验。试验结果与仿真结果吻合,电磁铁性能较好,但仍存在需改进的问题。     

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.     

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.     

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.     

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.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.