浮式钻井平台升沉模拟系统设计

设计电液比例阀控制非对称油缸模拟钻井平台升沉运动的实验系统,建立阀控缸的动态方程并用Matlab进行仿真。设计测控系统并采用PID和死区P控制相结合的方法控制比例阀,有效减小了死区对控制精度的影响。实验结果表明,该模拟系统可实现较高精度的位移跟踪。     

深海作业装置轻载主动型多维运动补偿器的研究

多维运动补偿器是保证深海浮式作业正常安全进行的重要装置之一.笔者提出了一种主要由升沉补偿机构、横移补偿机构和纵移补偿机构组成的轻载主动型多维运动补偿器的设计方案,设计了适合于主动运动补偿器的复合控制器;建立了运动补偿器的仿真模型和升沉补偿机构的模拟试验台.仿真和实验结果都证明了所提出的轻载主动型多维运动补偿器的设计方案是可行的,所设计的复合控制器是有效的.     

基于“PC+DSP”型开放式数控系统控制器的设计

设计一种“PC＋DSP”型开放式数控系统的运动控制器。阐述了控制器系统的硬件结构、工作原理、软件组成模块和主机与DSP之间的通讯系统。设计的“PC＋DSP”型控制器实现不同硬件的功能模块,实现控制器与多种类型的驱动器连接,增强了控制器与驱动器类型的兼容性和复杂控制算法的计算能力。     

海洋升沉模拟系统设计与控制算法研究

为了模拟海洋钻井平台的升沉运动规律,设计并搭建了一套基于电液比例阀控马达的位置伺服系统,建立了系统数学模型,对控制算法进行了数值仿真与实验研究,采用逐步细化的分段PID方法实现了模糊PID算法。研究结果表明:带死区补偿的模糊PID算法稳定性好、控制精度高,实现了带载状况下高精度的升沉运动模拟,满足性能要求。     

主动式钻柱升沉补偿模拟实验台控制系统设计

根据主动式钻柱升沉补偿系统控制原理,设计并搭建了主动式钻柱升沉补偿系统模拟实验台。利用Matlab/Simulink的x PC target模块搭建实时控制系统,将模糊PID控制器应用在升沉补偿控制系统中,并进行了实验。利用Lab VIEW软件开发了上位机界面。结果表明:基于模糊PID的控制系统具有良好的补偿性能,能够补偿高低不同频率的升沉运动。     

神经网络PID控制的液压驱动主动升沉补偿预测控制研究

为了提高船舶在海面上作业时补偿精度,采用BP神经网络PID控制方法,并对船舶升沉运动输出误差进行仿真。建立船舶主动升沉补偿系统简图,分析船舶升沉运动工作原理,给出液压缸驱动传递函数。引用BP神经网络算法,采用梯度下降法对BP神经网络加权值进行修正,通过学习速率来补偿控制系统输出误差,从而实现PID控制器参数在线调节。在受到不同负载影响状况下,采用MATLAB软件对船舶升沉运动补偿精度进行仿真,并且与PID控制补偿精度进行对比。结果表明:采用PID控制器,船舶升沉运动输出误差较大,控制系统反应速度较慢;而采用BP神经网络PID控制器,船舶升沉运动输出误差较小,控制系统反应速度较快,同时,随着负载质量的增加,输出误差就会增大。采用BP神经网络PID控制系统,响应速度快,补偿精度高,提高了船舶在海面上作业定位精度。     

直驱绞车型升沉补偿系统模拟实验台液压系统的研究

提出了一种基于直驱容积控制用来模拟绞车型升沉补偿系统的实验台方案,利用AMESim软件搭建了该系统的模型,确定了系统的结构和参数,设计了一个伺服电机调速控制和变量泵调排量联合控制器和能量计算器,并对其补偿特性仿真分析和整个系统的能量值计算。结果表明:该系统具有良好的补偿特性,所提出的实验方案可行,控制器的设计能够较好地实现直驱联合控制。能量值计算表明复合控制相对单一的伺服调速控制或单一变排量控制具有明显节能效果。这一成果为实验台的搭建提供了参考。     

升沉补偿模拟试验系统的设计与实验研究

提出和研制了深海采矿扬矿管的主动型升沉补偿模拟试验系统，实现了采矿船的升沉模拟和升沉补偿模拟，并进行了实验研究。实验的结果证明，采用电液比例阀控缸执行机构进行主动升沉补偿的方案是可行的和有效的，采用高性能的电液比例方向阀和合适的控制策略可以获得很高的升沉补偿精度。     

TSC型动态无功补偿半物理仿真系统设计

针对在研究冲击性负荷的无功补偿策略时面临的实验条件苛刻、成本高、危险性大等问题,提出了一种基于QuaRC平台和DSP控制器的TSC型动态无功补偿半物理仿真系统。根据典型冲击性负荷——点焊机的实际工况,在仿真环境中建立了实验对象,选取了一种无功补偿策略并在DSP控制器中实现。仿真结果符合实际情况,验证了本系统设计方案的合理性。     

盾构土压平衡电液模拟系统的研究

提出一种基于液体动力控制原理的盾构土压平衡电液模拟系统。根据土压平衡系统数学模型，建立电液物理模拟系统，通过调节模拟系统的电液控制变量或参量，来实现盾构土压平衡系统的进、排土工况和土质、推进速度等干扰变化工况的模拟。实验证明：该模拟系统原理可行，模拟方便，试验效率高，参数调节范围宽，适于强化试验。     

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。