基于改进Freeman-Newell模型的机械产品概念设计过程研究

在引入行为信息的基础上,对Freeman－Newell模型进行了改进,建立了基于功能和行为的载体认知模型,描述了设计过程中单元求解过程;基于该载体认知模型构造了概念设计过程模型－概念空间;采用布尔矢量/矩阵对概念空间中设计元素之间的关系进行了描述,使之便于计算机的表达和操作,在此基础上,给出了概念设计过程的形式化描述。最后以工业平缝机为例对所述模型和方法进行了说明。     

合金元素对反应堆压力容器用低合金钢的影响

选择三种反应堆压力容器用低合金钢,考察主要合金元素C、Cr、Ni等和微合金化元素Ti、B等在一定范围内对材料连续冷却过程中相变及淬硬性的影响。结果显示,增加主合金元素和添加微合金化元素可以改变材料在连续冷却过程中的相变行为,显著提高合金的淬透性和淬硬性。     

集成环境中产品装配仿真过程快速显示算法的研究

除包括产品装配模型外 ,当装配场景引入装配工艺、工装乃至工人作业模型时 ,产品装配仿真若继续保证较理想的可视化效果 ,对仿真实现算法、尤其是装配过程显示算法的运算效率提出了更高的要求。本文拟对在这种虚拟的集成环境中开展装配仿真的过程显示算法的专门研究 ,提出了基于向量的过程插补算法。首先 ,引入工作空间和元件空间等概念 ,提出用元件空间表示元件在运动中的位置 ,以此作为建立算法的基础和依托 ;接着 ,介绍基于向量的过程插补算法的核心———元件空间的位置和坐标轴向的插补方法及元件的空间变换算式 ;然后 ,简述此算法在自行开发的飞机装配型架CAD(FixCAD)系统中的实现以及在飞机装配过程仿真中的应用 ;最后 ,总结本算法的特点。     

基于特征约束关系的航天器大部件装配机器人机型设计方法及应用

面向狭长任务空间航天器大部件装配的定位调姿需求,提出一种装配机器人机型设计方法。该方法以大型构件装配对接过程中存在的主要特征为和空间约束为主要参考,结合空间自由曲面几何理论,总结装配过程中存在的多种典型特征,基于装配特征对应的数学描述,建立装配几何特征到机器人运动维度的映射关系;定义装配过程中轨迹规划涉及到的多种空间、位姿状态的表示方法,明确轨迹规划中的各类约束相互关系,确定机器人运动的边界范围。以典型作业环境空间站工作舱为例,研发基于PPRRPR构型的航天装配机器人。从机构构态和运动特征两个方面,结合串/并联机构的优势以及在对应约束空间下的行为特性,进一步提出基于机构行为特征的机器人优化设计方法,建立混联装配机器人的概念模型,为特定任务环境下装配及搬运大型装备的机构设计提供了一定的参考。     

精密光电测试转台热特性仿真分析

本精密光电测试转台用于高精度星敏感器的地面标定检测系统,其置于地面模拟空间环境中,要求其在恶劣的模拟空间环境中具有极高的精度.为了研究精密转台在模拟的空间高、低温真空环境中的变形特点及工作精度,首先分析了转台所处的高、低温真空环境的特点,给出了转台在高、低温真空环境中的主要传热途径,然后合理地选择了转台材料并设计了转台的机械结构,最后应用ANSYS有限元分析软件对转台做了热-结构耦合仿真分析.通过仿真分析,得到了转台在两个极限温度(-60℃和90℃)环境中达到热平衡时的温度变化特性和整体变形量,进而得出了变形对转台在高、低温真空环境中精度的影响.结合对转台的使用精度要求,对转台进行了结构优化设计,最终使转台达到了所需要的工作精度要求.     

交互操作行为驱动的手机产品人机工程设计

针对有复杂交互操作行为需求的手机产品,研究了利用交互操作行为对产品形态进行驱动设计的方法.细致分解了手机的人机交互过程,对持握和按键两个关键的操作行为进行了实验研究和实测数据的统计分析,获得了手机在掌中的定位特征,以及多键按键操作的综合舒适度和准确率的评价指标,并计算了相关的影响参数.基于编码表达式建立了手机产品的设计模型,利用遗传算法原理编写了手机设计方案的求解算法,通过问题构建、自动求解和交互求解三个过程在方案解空间中搜索最优方案.开发了交互操作驱动的手机设计原型系统,初步实现了求解过程.研究表明,利用交互操作行为对产品形态进行驱动设计是可行的,交互行为的表达方式和产品的编码设计质量对设计结果有较大影响.     

基于多色集合理论的制造质量影响因素关系网模型

为了给设计人员提供全面有效的设计决策支持信息,提出将制造过程中的质量影响因素,即人、机器、材料、方法、环境等信息反馈到设计过程,分析了制造质量影响因素对设计的支持,建立了制造质量影响因素及其属性之间的层次关系模型,以及支持设计决策的制造质最影响因素关系网.利用多色集合理论,能清楚表达集合统一颜色与集合元素及元素颜色之间关系的特点,给出了制造质晕影响因素及其关系网的多色集合数学描述.以齿轮工艺设计为例,构造了齿形加工过程的制造质量影响因素关系网,并建立了齿形加工过程的多色集合关系网模型.     

压力容器的无量纲设计法

依照GB150—1998《钢制压力容器》和JB4732—1995《钢制压力容器———分析设计标准》,并参阅其它国家的标准,分析总结了现行标准的设计步骤和存在的问题,由此提出了一种新型的压力容器设计法———无量纲设计法,并以卡箍紧固结构中的平盖为例,给出了此方法的计算与应用过程。通过此方法可以很方便地设计整体结构相同和局部结构相同的压力容器。     

元素形态分析及其在环境保护中的应用

元素不同形态造成其化学、生物效应差别很大,决定它们在生态环境中和生物体内化学行为,表现出不同化学、生物效应及在环境中的迁移特征,研究元素形态对于了解环境生态和人体健康具有重大意义。元素形态分析比传统元素总量分析更迈出一大步,进入了一个更深层次,使人们面对环境中各种元素更扩大了视野,更清楚元素形态特征和迁移规律,也更有助于人们采用更合理方法减少或消除环境中污染物,保证生态环境可持续性发展。     

关于培养机械制造工艺设计能力的研究

随着机械加工行业的发展与进步,机械制造工艺设计已经成为机械加工中的关键。机械制造工艺主要是对机械制造方法和过程进行设计,实现对整体工艺的控制。在该过程中,相关人员要严格按照操作程序,使用安全、方便的安装工件,将设计图纸转化为产品。在进行机械制造工艺设计的过程中,要注意综合企业单位所提供的丰富社会资源和机械制造资源,为设计人员创造良好的机械制造工艺设计能力培养空间,从本质上提高机械工艺的可行性和创造性,促进我国机械制造行业的发展。     

腐蚀环境下飞机结构疲劳全寿命评估模型

腐蚀环境作用下飞机结构疲劳全寿命评定是飞机结构疲劳断裂分析技术发展的趋势。介绍结构疲劳全寿命的研究现状,在此基础上提出基于不连续状态腐蚀与疲劳交互作用下飞机结构的全寿命评估模型。该模型能将环境影响下的点腐、剥蚀的演化不连续状态(evolving discontinuity state,EDS)纳入全寿命分析框架中。模型的构建能为飞机结构腐蚀疲劳全寿命评定提供技术支持。最后,对全寿命模型的进一步研究提出建议。     

Modeling of epoxy dispensing process using a hybrid fuzzy regression approach

In the semiconductor manufacturing industry, epoxy dispensing is a popular process commonly used in die-bonding as well as in microchip encapsulation for electronic packaging. Modeling the epoxy dispensing process is important because it enables us to understand the process behavior, as well as determine the optimum operating conditions of the process for a high yield, low cost, and robust operation. Previous studies of epoxy dispensing have mainly focused on the development of analytical models. However, an analytical model for epoxy dispensing is difficult to develop because of its complex behavior and high degree of uncertainty associated with the process in a real-world environment. Previous studies of modeling the epoxy dispensing process have not addressed the development of explicit models involving high-order and interaction terms, as well as fuzziness between process parameters. In this paper, a hybrid fuzzy regression (HFR) method integrating fuzzy regression with genetic programming is proposed to make up the deficiency. Two process models are generated for the two quality characteristics of the process, encapsulation weight and encapsulation thickness based on the HFR, respectively. Validation tests are performed. The performance of the models developed based on the HFR outperforms the performance of those based on statistical regression and fuzzy regression.     

JIT approach to integrating production order scheduling and production activity control

Two of the most desirable features in integrating production order scheduling and production activity control is sustaining a finite workcentre capacity assumption for accurate production order scheduling, and efficiently performing a what-if sensitivity analysis to handle the dynamic uncertainties in production activity control. A finite workcentre capacity assumption leads to too many constraints that tends to slow down the computation process, and a what-if analysis tends to put too much strain on the design of the database system for production activity control. With a finite workcentre capacity and what-if sensitivity analysis capability as the basis, a holistic approach towards production planning and control is emphasized in this paper by simplifying the system based on JIT principles such as shallow levels in bill of material, a pull type backward planning and a clear identification of the type of operational environment for which the designed system is readily applicable, and data integrity by tight integration of the various modules in production planning and control. As an illustration, a system is designed and has been successfully applied to a rapidly changing made-to-order printed circuit board manufacturing environment.     

Constrained behavior manipulation for interactive assembly in a virtual environment

Interactive assembly based on virtual reality offers users an opportunity to interact with a virtual prototyping rather than a physical one and to validate assembly performance of products in a realistic way. Such evaluations could be available very early in the product development process ahead of any physical prototyping. The reduction or elimination of physical prototyping needed for assembly performance validation can substantially shorten the product development cycle and reduce development cost. Although virtual reality technology provides users an intuitive and immersive 3D interactive interface, it tends to be inaccurate because humans have difficulty in performing precise positioning tasks. Therefore, it is necessary to implement effective motion manipulation for assembly operations so that users can perform precise positioning efficiently in virtual assembly systems. This paper presents a constrained behavior management approach that realizes assembly relationship recognition, constraint solution and constrained motion for interactive assembly in a virtual environment. A constrained behavior manager (CBM) has been developed and applied in virtual assembly systems. Test cases confirm that constrained behavior manipulation proposed in this paper not only increases the efficiency of assembly relationship recognition, but also facilitates assembly interaction in a virtual environment.     

Impact Fretting Wear Behavior of Alloy 690 Tubes in Dry and Deionized Water Conditions

The impact fretting wear has largely occurred at nuclear power device induced by the flow-induced vibration, and it will take potential hazards to the service of the equipment. However, the present study focuses on the tangential fretting wear of alloy 690 tubes. Research on impact fretting wear of alloy 690 tubes is limited and the related research is imminent. Therefore, impact fretting wear behavior of alloy 690 tubes against 304 stainless steels is investigated. Deionized water is used to simulate the flow environment of the equipment, and the dry environment is used for comparison. Varied analytical techniques are employed to characterize the wear and tribochemical behavior during impact fretting wear. Characterization results indicate that cracks occur at high impact load in both water and dry equipment; however, the water as a medium can significantly delay the cracking time. The crack propagation behavior shows a jagged shape in the water, but crack extended disorderly in dry equipment because the water changed the stress distribution and retarded the friction heat during the wear process. The SEM and XPS analysis shows that the main failure mechanisms of the tube under impact fretting are fatigue wear and friction oxidation. The effect of medium(water) on fretting wear is revealed, which plays a potential and promising role in the service of nuclear power device and other flow equipments.     

我国高校“精品实验项目”的调查研究

以多种方式对同济大学等一批高等院校进行＂精品实验项目实施情况＂的专题调查,总结得出：以新的理念和方法建立＂精品实验项目＂的设计思想,在实验过程中要更注重方法,要培养团队精神和整体观念。     

增压器叶轮三维重构实现技术研究

对存在干涉问题的复杂零件的逆向工程实现技术进行了深入研究。提出了不同于铣削层去法的机械去除测量方法,对零件的数字化、数据点云的重定位以及三维重构的全过程进行了详细地阐述,并对逆向工程整个过程存在的误差进行了分析和计算,确保了逆向工程的整体精度。     

一个实用的冲压工艺卡片生成和管理系统

介绍了一个实用冲压工艺卡片生成和管理系统的设计和实现。阐述了该系统的功能、运行环境以及应 用情况。利用该系统可以快速编制冲压工艺卡片并对大量的工艺卡片进行有效的管理。     

基于OpenGL和VC++的轴向振动钻削仿真技术的研究

论述了基于OpenGL的轴向振动钻削仿真的实现方法,构建了轴向振动钻削仿真系统的总体结构。该系统采用Pro/E对麻花钻进行几何建模,并利用Rhino转存为3ds文件格式。然后利用OpenGL和VC++将3ds文件导入仿真环境,利用重画技术和动态双缓冲技术对动态物体进行行为建模,从而模拟出整个轴向振动钻削过程。     

计算机辅助产品方案设计方法研究

方案设计一直是传统CAD系统的薄弱环节。通过对产品方案设计过程的研究,建立了产品的功能结构树和功能关系模型,通过引入“虚拟组件”的概念,采用功能结构与或图实现了产品功能到结构的映射,并利用基于实例的推理（CBR）技术,建立了基于实例的功能－结构整体映射方法,以加快结构方案设计进程。这些方法为计算机辅助产品方案设计的实现进行了有益的尝试。