基于集成学习算法的可持续模块划分方法

随着客户对可持续产品需求的增加,针对产品功能和结构属性的传统模块化设计,正逐步转向可持续模块化设计。然而当前的模块划分方法更注重于对模块化指数的优化迭代,忽略了产品多组件间的信息传递和反馈。为此,提出一种集成学习算法的可持续模块划分方法。首先,面向组件间的回收性、材料和寿命因素,构建产品的综合DSM模型。其次,提出集成学习算法的弱分类器构建规则和强分类器结合策略。最后,通过颚式破碎机案例验证了所提模块划分方法的可行性,集成学习算法同直接聚类和遗传算法的模块划分结果对比,表明所提方法各模块组件更接近DSM的对角线。     

淬火机床的模块化设计应用研究

针对淬火机床制造企业普遍存在的开发能力薄弱、设计周期长、制造困难、成本高昂等问题,在分析现有模块划分方法的基础上,对淬火机床的模块化设计进行研究。通过基于参数的设计结构矩阵DSM描述淬火机床功能部件之间的关系。以模块的高内聚性、模块间低耦合性为划分原则,利用层次分析法AHP确定相关性指标权重,构建功能部件综合结构相关矩阵。结合层次聚类法,通过MATLAB软件作出谱系聚类图,以获得划分方案,实现淬火机床的快速开发。通过模块化设计,可以缩短淬火机床研发周期,实现大批量生产条件下的个性化生产,快速响应市场和用户的多样化需求,使其适应日益激烈的市场竞争。     

基于分层设计结构矩阵的航空产品工装模块划分

工装模块划分是航空产品工装模块化设计的关键环节。为提高航空产品工装模块划分的准确性,提出基于分层设计结构矩阵的航空产品工装模块划分方法。基于航空产品工装结构图建立分层设计结构矩阵,通过遍历构建全局设计结构矩阵,并运用聚类分析法得到工装模块划分的初始解,之后应用联系成本计算方法对划分结果进行评价,获得最优的模块划分方案。以某型号航空散热器焊接总装夹具为例,验证了该设计方法的有效性和可行性。     

分层设计结构矩阵在产品模块化设计中的应用研究

为了适应模块化设计的发展需求,建立了基于BOM的分层设计结构矩阵,并提出了相应的产品设计过程任务规划的一般步骤。然后,从分层设计结构矩阵的角度,研究了各DSM间的信息交流与遍历方法,方便下一步任务解耦和任务重组策略的实现。最后,以二级圆柱齿轮减速器为例,说明了规划方法的应用,推动了模块化的产品结构管理、组织结构管理和过程管理的实现。     

模块化设计中模块划分方法的研究

作为实现产品多样化的主要途径,模块化设计技术在越来越多的行业中得到了广泛应用。模块划分是模块化设计技术的关键,已成为国内外的研究热点。模块划分是指依据模块划分的原则,从不同的角度将产品划分为若干基本单元,最后采用聚类方法将这些基本单元聚类为模块。因此,模块划分涉及到三个关键问题：模块划分的原则、模块划分的角度和模块的聚类方法。研究对象不同,其模块的划分方法也往往不同。在研究相关文献的基础上,分析总结了模块划分的基本概念及其研究现状,对模块划分涉及到的这三个关键问题分别进行了系统阐述,从而为不同类型产品的模块划分提供理论指导;最后指出了模块划分的进展和存在的不足之处,为今后的研究提供参考。     

模块化快速设计中的产品信息模型研究

针对面向产品快速设计的模块化技术特点,提出了建立模块化产品信息模型的思想.在模块化产品矩阵规划方法的基础上,将模块化产品模型分解为产品方案模型、模块模型和接口模型三种模型.文中阐述了三种模型的信息组成和数据结构,为建立产品快速设计软件系统提供了技术基础.     

基于客户需求的产品绿色模块划分方法研究

为满足客户对产品的绿色设计与模块要求,从客户需求的角度建立产品绿色模块划分模型。文章提出基于客户需求的产品绿色模块划分方法,获取产品绿色需求后采用李克特量表法进行参数处理,利用因子分析得到产品绿色需求重要度。通过综合考虑产品零部件之间的基本属性和绿色属性,建立了产品的综合矩阵,以模块度为适应度函数,运用遗传算法计算出产品最佳的绿色模块划分结果,实现了产品绿色模块聚类划分。最后以冰箱为例,验证了该方法的可行性和有效性。     

面向产品族演进的模块通用性研究

模块通用性程度的度量对模块化产品族设计或再设计以及演进过程具有重要的意义。分别从基于零部件的通用性指标和面向参数化产品族的通用性指标两个方面进行研究现状的分析,进一步指出了模块通用性与产品族演进关系。在此基础上,提出了基于模块化产品族结构模型的模块通用性指标,即由模块化产品族的模块功能、结构和特征参数三层要素合成,可以分别实现单个模块通用性和模块化产品族整体通用性的衡量,最后以轮式装载机产品族为例说明该方法的有效性。     

基于模块化的变型设计技术研究及CAD系统框架的构建

模块化设计方法和技术是支持产品族开发和快速变型设计的重要途径.文章对基于模块化的变型设计技术进行了深入的研究,并着重探讨了面向产品族的模块化产品结构构成模式及面向产品族的模块化变型设计的一般过程,建立了基于模块化的变型设计CAD系统的功能结构.     

产品快速设计系统中的模块划分及建模方法

模块化技术是产品快速设计的使能技术。论述了产品快速设计中的模块化技术。介绍了模块的定义、基于装配结构的模块划分和功能模型到产品模型映射技术。提出了智能模块体技术和构建策略，以利于模块体修改、移植和标准化。最后给出了应用上述方法及技术建立的产品快速设计系统的框架。     

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.