基于自动检查系统的可制造性设计规范应用研究

由于航空航天信息化建设的不断推进,工艺性审查工作急需由人工转为计算机自动辅助检查,此项工作是信息化平台建立的重要一环。以自身企业实例出发,对基于自动检查系统的可制造性设计规范进行了初步探讨,总结了建设平台的共性规律,确认并优化了相关工艺性审查数据,为企业建立自动工艺性审查工作提供了有益的方法和尝试。完善的自动工艺性审查平台,实现了设计、工艺协同工作,为技术人员工艺性审查工作提供了便捷的途径,提高了生产效率,也将为信息化平台的搭建奠定坚实的基础。     

飞机蒙皮自动制孔工艺设计研究

基于MBD的飞机蒙皮自动制孔工艺设计是飞机数字化制造工艺关键技术之一,根据飞机装配过程中自动制孔工艺设计的特点和要求,将制孔信息分为基准孔、夹紧孔、自动制孔三类,对制孔需要的点位、法矢、连接件材料、材料顺序、夹层厚度、夹层厚度顺序、标准件信息等提取的关键技术进行了研究,通过CATIA/CAA平台,开发了飞机自动制孔工艺设计软件,实现了制孔信息的分类、提取、规范存储等,有效地解决了飞机蒙皮自动制孔工艺设计难题,提高了工艺设计效率和飞机数字化制造水平。     

飞机标准件的自动筛选与匹配技术研究

针对飞机装配设计中标准件选用效率不高的问题,研究了基于飞机标准件信息的自动筛选技术。通过构建匹配度函数,实现标准件的自动匹配功能。通过实例表明,自动筛选与匹配技术在飞机的快速化装配设计中具有重要意义。     

飞机钣金制造机床设备数据库及其集成应用研究

为实现飞机钣金成形机床设备数据的系统化、规范化管理,解决系统之间的信息交互与集成问题,结合飞机钣金成形机床设备的使用情况,对飞机钣金成形机床设备进行了科学分类,采用J2EE平台开发了基于Web的飞机钣金成形机床设备数据库系统;面向飞机钣金零件制造的工艺性评估、制造指令设计、工装设计、工艺参数设计等系统,利用J2EE平台的适配器,采用XML描述了飞机钣金成形机床设备信息,解决了机床设备数据库与飞机钣金工艺设计各系统之间的信息集成问题;最后通过实例对上述方法的有效性和实用性进行了验证。     

MBD设计模型的工艺性审查研究

针对目前三维零件工艺审查过程中存在的问题,进行MBD设计模型的工艺性审查研究。利用Pro/E为支撑软件,在Visual Studio 2005软件的编译环境中,通过编程调用Pro/Toolkit工具中的函数,对Pro/E软件进行二次开发,实现MBD设计模型工艺信息的识别、提取、修改和存储等功能。对于工艺审查的研究能极大地降低工艺人员的工作量,提高MBD设计模型的工艺审查效率。     

交互式MBD模型工艺审查方法研究

针对目前计算机辅助工艺审查过程中存在的评价特征种类不全面、规则库维护困难的问题,以基于模型定义(Model Based Definition, MBD)的设计模型为研究对象,开展了工艺审查方法的研究。利用获取到的MBD模型形状和非形状特征数据集,采用交互式方法进行特征参数库用户自定义维护与扩展,同时借助知识工程相关方法,以UG软件作为基础平台,以Python语言作为编程语言,利用二次开发接口NXOpen构建工艺审查专家系统,实现对零件结构工艺性和可加工性的工艺审查。     

在产品开发中如何做好工艺性审查工作

随着科学技术的进步,工艺技术的发展,为弥补产品设计人员在产品结构工艺方面的不足,保证所设计的产品图样具有良好的工艺性,规定工艺部门必须在产品技术设计阶段进行"工艺性分析",在产品工作图设计阶段进行"工艺性审查",这两个环节的全过程称为"产品设计的工艺性审查",习惯上简称"工艺性审查"。当前产品技术越来越先进和复杂,产品更新换代日益加快,市场竞争日显激烈,迫使企业加快产品开发速度,缩短产品开发周期。在这种情况下,强调产品设计工艺性审查的重要作用,研究如何做好工艺性审查工作,无疑具有非常现实的意义。一工艺性…     

ISO9001质量认证中的工艺工作

在ＩＳＯ９００１质量认证中,工艺工作牵扯到方方面面,工作量大,工作面广,是质量认证工作中非常重要的一环,各项工作都要做得周密细致。下面就ＩＳＯ９００１质量认证标准的有关条款的工艺工作给予论述。在新产品设计控制中,工艺人员主要负责产品的工艺性审查、工艺设计、工装设计,进行新原理、新结构、新技术、新材料、新工艺应用的研究,以及产品试制和生产过程中的技术服务。一、工艺性审查有关专业人员要对产品图样及设计文件进行工艺性审查,主要是审查产品结构的合理性和加工的工艺性,对于不利于安装的结构及不便加工的零件,…     

飞机导管数字化快速敏捷制造技术

介绍了国内外飞机导管数字化制造技术的应用现状,分析了国内导管制造技术在新机研制过程中常见的技术问题,提出用三维模型代替实样作为导管数控弯曲与检验、组合夹具设计与制造的方案,并通过规范化建模、软件开发,建立了飞机导管数字化敏捷制造集成系统,实现了导管的快速工艺分析、组合夹具的快速设计,最后给出了应用实例。     

基于成组技术的复杂零件数控自动编程系统研究

针对船用柴油机复杂零件在利用CAPP/CAM技术进行数控编程中出现的问题,分别采用了优先级分级检索策略和加工模板技术,对CAPP/CAM中的相似性进行了挖掘与处理;并通过运用UG二次开发技术和SQLserver数据库技术开发出数控自动编程系统,对从CAPP/CAM中挖掘出的相似性加以利用,实现了UG平台上加工模板定制、与CAPP工艺的匹配和数控自动编程;应用实例验证了系统的可行性与实用性,能够大大提高复杂零件数控编程的效率和编程质量。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.     

Fractional order nonsingular terminal sliding mode control for flexible spacecraft attitude tracking

This paper investigates a fractional terminal sliding mode control for flexible spacecraft attitude tracking in the presence of inertia uncertainties and extern...     

奥氏体不锈钢表面双辉等离子渗锆的动力学

利用双辉等离子渗金属技术在0Cr18Ni9Ti奥氏体不锈钢表面制备了一层均匀、致密、呈良好冶金结合的渗锆合金层,并对1 060℃下的渗锆动力学进行了研究。结果表明:随着距锆合金层表面距离的增加,锆元素的含量呈梯度递减,扩散系数逐渐减小,而扩散激活能逐步增大;在1 060℃采用双辉等离子技术渗锆时,渗锆合金层表层的空位密度为2.945×(1012~1013)cm-2,与相同温度下采用常规渗金属工艺相比,提高了1~2个数量级。     

气化炉三维扫描测量与数据处理

以德士古气化炉耐火砖的内壁蚀损检测设备为基础,对采集到的点云数据做了进一步处理.通过对数据的筛选和剔除,实现了数据点的平滑降噪细化和精简.然后利用点云对整、网格划分和分色显示等方法,最终完成了内壁腐蚀情况的三维建模.重点讨论了点云数据的预处理及后处理的方法,并根据内壁耐火砖的腐蚀阈值,提出了一种气化炉内壁腐蚀区域的识别与分割方法.对耐火砖的腐蚀分析、气化炉的生产与维修提供了可靠依据,并在工程应用中获得了一致认可.