计算机辅助机械产品概念设计技术探讨

提出一个支持机械产品“需求分析 概念设计 详细设计”全设计过程的计算机辅助集成设计工具的框架 ,介绍产品设计过程模型 ,面向全生命周期基于广义特征技术的产品信息建模方法、概念设计方法以及设计过程各阶段的集成技术。     

基于联合学习的概念设计知识抽取与图谱构建

为提高产品概念设计过程中设计知识获取效率，解决设计知识碎片化、推理性差、可视化程度不高等问题，提出了基于联合学习的设计知识抽取与图谱构建方法。首先，根据设计知识需求和产品概念设计流程，构建了面向产品概念设计的设计知识图谱框架，然后，分析了设计知识提取过程中实体关系重叠问题，建立了基于联合学习的设计知识抽取模型，该模型通过ELECTRA算法进行语义编码，利用联合学习方法将实体关系抽取转换为各关系上两实体映射。通过真实设计数据和DuIE公共数据集对比实验表明，该模型知识抽取效果显著优于对比模型。最后，将该方法应用于文化创意产品设计知识图谱开发，为设计师提供关联化、可推理、可视化的设计知识，辅助进行产品概念设计。     

集成产品设计系统的研究与开发

CAD仅仅用作绘图工具而没有合理的应用策略 ,是不经济的。未来的CAD应该支持“需求分析—概念设计—具体化设计—详细设计”全设计过程。介绍了产品设计过程模型 ,把产品设计过程分为七个阶段 ,提出了一个集成产品设计系统的结构框架 ,以支持产品设计全过程。讨论了实现设计过程各阶段集成的三个关键技术 :基于特征的面向产品全生命周期的产品建模技术、STEP标准和API技术。     

产品概念设计中方案实例的表达与方案生成

概念设计方案实例的知识表达关键是将CBR应用于产品概念设计。将行为信息引入公理化设计中，建立了扩展“之”字映射；在此基础上，构造了概念设计方案实例的知识表示模型——域结构模板；给出了基于域结构模板的多方案生成过程。以高速链式平缝机为例对所述模型和方法进行有效性验证。     

产品全生命周期信息模型研究

为了建立完整、可重用、高度一致的产品全生命周期信息模型,提出了一种产品全生命周期模型的体系框架。该框架由面向产品生命周期的过程模型、扩展企业资源模型和产品信息模型组成。重点对组成产品生命周期的需求分析阶段、概念设计阶段、工程设计阶段、产品制造阶段及产品支持服务阶段各模型的组成、表达及其各阶段模型的演化过程进行了研究。在此基础上,提出了基于应用层、服务层和数据层的3层信息体系结构的产品全生命周期信息集成框架,支持网络环境中产品数据分布式互操作。     

智能产品模型的数据组织结构研究与应用

基于复杂系统集成设计环境,构建智能产品模型的数据组织结构,并应用于某卫星概念设计实例中。该模型由结构、功能和行为组成的产品模型,以及环境变量组成。用结构模型、功能模型描述产品全生命周期不同阶段产品的一般信息;行为模型是某个状态点上产品对环境的反应,由这三个模型组成的产品状态模型表征智能产品模型的静态特性;而环境变量表达产品全生命周期不同阶段产品信息之间的联系,是产品信息的发展进程,表达智能产品模型的动态特性。     

基于企业资源的设计重用研究

在中国国家“十五”科技攻关重大项目《沈阳市用高新技术改造传统装备制造业示范工程》支持下，研发大型成套装备产品设计开发支持系统技术，解决产品设计开发方法问题，报告基于企业资源的设计重用研究成果。 通过对当前中国大陆机械制造企业产品开发设计现状的分析，基于产品并行和协同设计理论，提出设计关系模型，以体现产品设计的并行、协同、面向全生命周期等属性；突出设计师对设计过程的触发和参与——在从概念设计到详细设计的过程中，设计师应能简捷有效地在一定层位对设计进行修改。 借助产品创新设计原理、方法及合理化工程等理论，分析产品开发与建模过程。以最大限度实现并行工程与协同工作环境的设计重用，提出基于并行工程的机械产品创新设计平台PDM概念。平台PDM由基础环境层、应用支持层、应用工具层及应用界面层组成。提出产品设计过程及产品结构物理模型，基于实例与特征技术、产品结构与PDM映射，建立数学模型、映射模型及实例模型，明确设计过程关系，使PDM系统成为实现概念设计重用的系统。     

基于数据挖掘的产品概念设计建模研究

在产品概念设计过程中，引入数据挖掘技术和方法，提出了基于数据挖掘的全息虚拟产品概念设计模型，开发了数据挖掘工具，建立了面向产品概念设计方案生成的数据仓库；研究建立决策树算法的数据挖掘模型，以支持度为目标，实现从所建立的机械产品库、设计规则库、领域知识库中挖掘相关数据、信息和知识，从而极大地支持机械产品方案创新设计过程。以机床传动机构设计为例，说明了采用决策树方法的数据挖掘模型来实现机械产品概念设计的功能结构映射过程。     

基于OWL本体建模的概念产品配置

提出了一种基于本体的产品概念设计信息建模方法，并以减速器的设计为例，从概念实体、概念属性及概念间关系三方面介绍了构建产品本体信息模型的方法，同时采用最新的Web本体语言——OWL进行描述。初步研究表明．基于本体的信息模型克服了传统设计模型know-whv、know-how在知识表达方面的欠缺，具有清晰、一致、完整等特点，可有效地保证设计质量并提高设计效率。     

产品全生命周期中面向客户服务的产品模型

将产品全生命周期划分为需求分析、概念设计、工程设计、加工制造、服务支持五个阶段,按照所划分的阶段,提出包括产品需求分析模型、概念模型、设计模型、制造模型和服务支持模型的体系框架,同时研究了各阶段模型之间的转换、集成、互操作方法。在此基础上,重点对产品生命周期中的产品服务支持阶段的模型进行了描述,提出了产品服务支持阶段的模型包括产品服务模型和客户信息模型,研究了从产品的其他阶段模型转化和构成产品服务模型的方法。     

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...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

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。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

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.