基于专家系统和神经网络的制造过程智能决策系统

提出一种基于专家系统和神经网络相结合的加工过程多目标优化智能决策方法,建立了专家系统和神经网络之间的信息交换机制,采用面向对象的方法设计了车削加工过程多目标优化的智能决策系统。     

基于CAPPFramework开发平台的锻造CAPP系统

本文基于集成的CAPPFramework框架和开发平台构建了锻造工艺的产品信息模型,建立了锻造工艺的知识库和规则库,应用数学模型决策、逻辑决策两种数学方法实现了工艺决策。并以某锻造分厂为例,建立了锻造CAPP系统。     

基于CAPPFramework开发平台的锻造CAPP系统

本文基于集成的CAPPFramework框架和开发平台构建了锻造工艺的产品信息模型,建立了锻造工艺的知识库和规则库,应用数学模型决策、逻辑决策两种数学方法实现了工艺决策。并以某锻造分厂为例,建立了锻造CAPP系统。     

基于近似替代模型的多工位高速锻造预锻模具优化

多工位高速锻造是一种节能减耗的先进成形技术,与传统的单工位多工序锻造有较大区别,不合适的预锻工位模具设计在生产中会造成载荷过大、锻件充填质量差、折叠等问题。文章提出了基于近似替代模型的多工位高速锻造预锻模具优化设计方法,采用拉丁超立方抽样方法构造初始样本点集,应用有限元软件获得响应值,并应用Kriging模型和BP神经网络模型建立真实问题的替代模型,来近似拟合预锻工位模具形状与成形载荷、成形质量之间的关系,并结合基于惩罚函数法的遗传算法求得最优解。以3工位高速锻造问题为例,经过优化取得了良好的效果,与初始设计相比,成形质量显著提高,成形载荷下降了40%左右。     

基于本体元模型的锻造知识管理系统建模与工艺推理

知识管理系统的首要问题是知识建模,知识模型直接影响着整个系统知识的获取、共享、重用和推理。文章运用领域本体思想对锻造知识进行分类、总结,提出一种基于本体元模型驱动的锻造知识管理模型,初步构建了锻造知识领域本体,采用框架概念图表示锻造知识。文章还结合锻造工艺知识,给出了本体元模型驱动和概念图框架知识表示模型在锻造知识管理中的具体应用,并提出一种适合于本体元模型的推理方法,并将该方法用于锻造工艺知识推理。本体元模型驱动的知识库构建方法在组织锻造知识时,具有构建速度快、良好的互操作和知识共享等优点。     

基于归纳学习的挤压锻造模智能优化技术

分析了基于人工智能中的归纳学习方法,提出了一种针对挤压锻造工艺优化的基于数值仿真归纳知识的混合优化方法,并通过一个挤压锻造的实例验证了该方法的有效性。     

矩形截面件径向锻造工艺优化

对于矩形截面件径向锻造问题,目前尚没有相应的锻造载荷、锻造功率和锻件质量相关的计算模型,以及工艺规划的标准。根据径向锻造变形特点,将平面变形条件下锻造载荷公式推广到矩形截面件锻造载荷计算,将预测圆截面件径向锻造锻透率的三角形法则推广到矩形截面件并进行了修正,提出一种锻造功率计算模型,计算误差都在10%左右。然后采用多目标加权的方法,将锻造效率、锻件质量和锻造载荷模型转化成单一的优化目标函数,对道次、压下率和送进率等工艺参数进行优化;同时,采用4个工艺实例验证了工艺优化算法的优化和评估能力,并最终将工艺优化算法写入软件,应用到径向锻造自动化生产过程。     

基于经济评价原理的矿床开发优化决策多目标集成系统

从系统论的观点出发，阐述了基于经济评价的矿床开发系统的概念，并以定性与定量综合集成方法为基础，分析了基于经济评价原理的矿床开发优化决策多目标集成方法并建立了其集成系统。该系统以矿床模型、矿床采选方案选择模型、成本与投资估算模型、财务评价模型为基础，以多目标分析模型为核心，形成了系统集成的总控模型，所建立的集成系统具有预测、模拟、优化与决策等集成化功能。结合实例，说明了该系统的初步应用。     

基于自由锻件特征模型的CAPP专家系统研究

通过引入特征技术,将工艺设计相关的自由锻件属性和信息抽象成特征的形式.提出建立锻件特征模型并以此为基础的CAPP专家系统的推理方法.介绍了基于锻件特征模型CAPP推理系统的结构,模型的结构组成与表达,特征的获取方式及专家系统及其推理机制.针对自由锻造的特点,提出将锻件特征转化为成形特征,并以成形特征为基础的锻造工序推理...     

基于OPC UA的典型塑性成形机床设备模型的研究与应用

针对当前国内缺少对塑性成形机床的信息模型研究的现状,以典型锻造车间的塑性成形机床为研究对象,提出一种塑性成形机床的信息模型建模方案。在确定好建模方法后,结合OPC UA信息模型的概念以及设备的物理模型,将设备的数据类型分为共有设备类型和私有设备类型,对这两种数据类型分别进行定义与建模,然后对信息模型进行实例化描述。最后根据实际工厂情况,提出了该信息模型在车间的不同布置方式与应用方法,从而实现设备与管理层系统的数据通讯,达到设备与设备、设备与系统的互联互通。为OPC UA在锻造行业的应用进行了探索与研究。     

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。