基于STEP的产品数据建模研究

在分析了并行工程、精节生产、智能制造等先进制造技术的特点后，提出了为实现ＣＡＤ／ＣＡＭ的真正集成，必须采用统一的信息模型，而基于ＳＴＥＰ的信息模型可满足产品生命周期各阶段对信息的需求。为此，本文探讨了产品生命周期信息需求，给出了—实现面向未来的制造技术基于ＳＴＥＰ的系统模型，并针对模具进行了分析     

注塑模集成产品信息模型研究

本文分析了注塑模系统建模特点，认为基于ＳＴＥＰ的建模策略可以满足系统模型的需要，并开发了注塑模集成产品信息模型，它由总体信息模型、特征信息模型、结构信息模型和辅助信息模型构成。     

“多视图”全局集成产品模型研究

并行工程是在信息集成基础上实现产品的并行开发。因此，需要一种集成化的全局产品模型来支持产品全生命周期各阶段的活动，以实现企业的产品数据共享。本文首先进行了机械产品建模分析，然后建立起以ＥＸＰＲＥＳＳ－Ｇ表达的全局集成产品模型信息需求关系，由此提出一种适合于并行工程开发框架的“多视图”全局产品模型。该模型以ＳＴＥＰ（ＩＳＯ１０３０３）标准的应用协议（ＡＰ）为基础，结合产品特征建模技术，提供了完整、无二义性、多视图方位的产品信息抽象模型。     

产品模型数据交换标准

产品模型数据交换标准（ＳｔａｎｄａｒｄｆｏｒＥｘｃｈａｎｇｅｏｆＤｅｆｉｎｉｔｉｏｎＤａｔａＭｏｄｅｌ,ＳＴＥＰ）是用于不同ＣＡＤ／ＣＡＭ系统之间信息交换的一个国际标准。ＳＴＥＰ技术提供一种不依赖于具体系统的中性机制,规定了产品设计、开发、制造,甚至于产品全部生命周期中所包括的诸如产品形状、解析模型、材料、加工方法、组装分解顺序、检验测试等必要的信息定义和数据交换的外部描述,因而ＳＴＥＰ是基于集成的产品信息模型。ＳＴＥＰ具有三个开发层次;应用层、逻辑层和物理层。ＳＴＥＰ采用ＥＸＰＲＥＳＳ语言进行…     

STEP技术在产品建模中的应用与实施

本文分析了数据交换技术的发展,提出基于面向对象和ＳＴＥＰ技术建模可以满足产品建模发展的需要,并分析了基于面向对象和ＳＴＥＰ技术建模的特点,针对注塑模开发了集成产品信息模型。     

注塑模集成产品信息模型研究

本文分析了注塑模系统建模特点,认为基于ＳＴＥＰ的建模策略可以满足系统模型的需要,并开发了注塑模集成产品信息模型。它由总体信息模型、特征信息模型,结构信息模型和辅助信息模型构成。     

STEP建模和集成方法应用探讨

ＳＴＥＰ是国际标准化组织制定的产品数据表达与交换标准，为ＣＡＤ／ＣＡＭ系统的开发提供了标准化的建模工具。本文在介绍ＳＴＥＰ标准的功能结构特点之上，分析ＳＴＥＰ在应用领域的实现和集成策略，以及探讨目前应用研究方法和主要研究方向。     

产品数据交换技术的研究进展与集成策略

评述了产品数据交换技术的研究进展，介绍了ＩＩＳＯ ＳＴＥＰ标准的内容和结构，提出了一种基于特征的集成化ＣＡＤ／ＣＡＭ产品模型结构，为研究以ＳＴＥＰ产品数据模型为基础的数据驱动型的ＣＡＤ／ＣＡＭ系统提供了新的集成策略。     

产品简介

基于ＳＴＥＰ的ＣＡＤ/ＣＡＰＰ/ＣＡＭ信息集成系统 1　项目简介基于特征的ＣＡｘ/ＤＦｘ信息集成是ＣＩＭＳ和并行工程的核心技术之一 ,是解决ＣＡＤ/ＣＡＰＰ/ＣＡＭ信息集成的有效方法。本项目的研究和开发内容包括 :(1)根据ＳＴＥＰ建模方法 ,参照ＳＴＥＰ标准应用协议ＡＰ2 14、ＡＰ2 2 4 ,充分考虑了制造工艺的需求 ,用ＥＸＰＲＥＳＳ语言建立了复杂结构件的特征信息模型 ;(2 )利用商品化ＣＡＤ系统的二次开发工具进行了特征二次建模 ,并开发了特征建模系统 ,建立了特征造型用户界面 ;(3)利用ＳＴＥＰ开发工具 ,开发了面向应用的ＡＰ…     

钣金冲模集成制造系统的产品信息建模

计算机集成制造是模具生产集成化和智能化的最高体现,建立钣金冲模产品信息模型是实现模具集成制造的基础。本文针对钣金冲模集成制造的功能模块,建立系统的功能模型,并给出结构化分析的 Ｉ Ｄ Ｂ Ｆ０ 图形表达;分解模具集成产品模型为制件模型、制件展开分析模型、工步设计模型、模具设计模型、零件设计模型、数控加工模型和模具装配仿真模型等,并用 Ｅ Ｘ Ｐ Ｒ Ｅ Ｓ Ｓ语言建立信息模型。     

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.     

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....     

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.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.