基于网络的CAD考试系统设计

CAD网络考试系统是一套基于C/S与B/S相结合的体系,采用SQL Server 2000数据库和先进的ADO技术开发,以组织客观、公正和科学合理的CAD考试为目的的考试系统.根据CAD发展趋势,开发出一套包括CAD理论、二维图形设计、三维图形设计和二次开发4个模块的试题库.该套系统是一套集考试题库管理、考试成绩管理和考试信息管理三位一体的综合性CAD考试管理系统.     

Automation in the design of EDM electrodes

Plastic parts, especially those designed for consumer electronics products, are becoming more compact and freeform in shape. This requires the construction of compact and delicate geometric features in the injection moulds that produce these parts. It is now common practice to employ electric discharge machining (EDM) whenever the conventional machining process fails to machine such delicate features. Although CAD/CAM systems are widely used in mould design and manufacturing, and specific commercial CAD/CAM systems that are customized for injection mould applications are also available, there are still no intelligent CAD tools that address the specific requirements of EDM electrode design. The aim of this research is to develop an intelligent CAD tool that supports EDM electrode design. This CAD tool uses a new technique that recursively splits the EDM region into sub-regions until machinable electrodes can be constructed. The CAD tool has been implemented and integrated into a commercial CAD/CAM system, and 40 different real designs has been used to test its capability in handling a wide variety of geometric shapes. Performance data show that the efficiency of the design process can be improved by at least 50%, with a potential to achieve 85% through improved implementation and further research.     

基于KBE与ActiveX的产品参数化设计研究

针对目前尺寸驱动参数化建模方法存在的不足,提出了程序外驱动参数化建模思想,利用面向对象方法开发了基于知识工程(KBE)的机械产品参数化设计平台.该平台以三维CAD系统API模块为接口,采用ActiveX Automation技术,通过消息数据通信,将.NET开发的设计系统与CAD/CAE软件进行无缝集成.以桥式起重机设计为例,在知识重用和产品信息共享的基础上快速实现三维建模与虚拟装配,为数字化设计与制造提供了高效,准确、实用的方法.     

基于STEP标准的通用有限元数据基的构成

在进行工程设计和产品设计时,通常需要应用有限元技术进行设计对象的力学分析,在这个过程中不仅会生成大量的数据,还需要在不同的有限元软件之间,不同的有限元前后处理软件之间,或者有限元软件与ＣＡＤ／ＣＡＭ软件之间进行数据交换,针对目前有限元软件主要采用点对点数据交换模式所存在的缺点,提出了建立为适的交换模式－有限元数据基的设想,并基于ＳＴＥＰ标准构建了有限元数据基的中性文件的表述形式及其ＥＸＰＲＥＳＳ描     

面向特征的CAD集成系统交互接口的设计

本文从ＣＡＤ／ＣＡＭ集成思想出发,认真分析了传统ＣＡＤ系统在集成过程中存在的问题。提出了一个基于制造环境的ＣＡＤ系统设计模式,并基于此设计了面向特征,具有工艺信息反馈和限制的ＣＡＤ交互接口,为设计者提供了一种自然的,能反映所设计零件形状的可能加工方式和一定的加工工艺分析信息的交互界面,并具备了图示化等特点。     

Product design logic for an intelligent product modelling system

Recent research in CAD systems has been conducted to realize intelligent processing. Several CAD systems and product modelling systems have been developed using AI techniques. However, in order to develop more intelligent CAD systems, the design logic which connects the functional requirement to the geometric and the technological information of the designed product must be evaluated.

A product model used in such intelligent CAD systems has to include not only the geometric and the technological information of the product but also the designer's thought process which explains the design logic.

Design logic is generally divided into two parts. One is the generalized design logic which is commonly used in the conceptual design of mechanical products. The other is the product specified design logic which is used in the fundamental and detailed design phase. Different logic is applied to each product. This type of design logic is often used in modification design and compilation design, where the dimensions of parts have to be modified according to different functional requirements. When the dimensions and accuracies of the products are defined in connection with the functional requirements through design logic, the CAD system can automatically make decisions according to the given requirements. In this paper, suitable presentation formats and processing functions for these two types of design logic are discussed.

The importance of design logic in product modelling is proven through several case studies in this paper. As a conclusion, the intelligent product modelling system is developed, which should expedite the progress of design automation in the near future. In conceptual design, the design logic is processed in the modelling system and the product structure, with the technological information decided automatically from the functional requirement. Automation in the detailed design phase is also facilitated by the modelling system using the product specified design logic in the product model.     

CAD在线考试系统的设计

CAD在线考试系统采用B/S三层体系结构,利用.NET技术实现了对题库的管理、试卷的自动生成,考生成绩查询等功能,采用SQL 2000为数据库。该系统根据CAD发展趋势,开发出一套包括CAD理论、二维图形、三维图形设计和二次开发4个模块的试题库。     

基于Surfacer二次开发的口腔固定修复CAD系统

口腔修复CAD系统是口腔固定修复CAD/CAM技术的重要组成部分。文章利用反求软件surfacer的二次开发功能,结合口腔修复学知识,研究开发了针对牙冠和嵌体的口腔修复CAD系统。应用结果表明该系统设计合理、界面友好、操作简便,设计的修复体精确度高、贴合性好,为个性化修复设计和制造奠定了基础。     

参数化CAD-CAPP系统技术的研究与应用

针对现代制造企业对信息集成的需求,研究了参数化CAD/CAPP系统的原理及相关技术.利用相似性原理、可重用性原理、实例推理技术、设计知识库技术、参数化技术开发了参数化CAD模块.开发了基于设计知识数据驱动、工艺知识约束修改典型工艺模板的派生式参数化CAPP模块.并建立了巷道式双立柱堆垛机参数化CAD/CAPP系统,实现...     

基于Web的车身设计CAD／CAE信息集成系统研究

针对车身开发设计中CAD、CAE子系统间相互独立，导致车身设计效率低的问题，开发了汽车车身设计CAD／CAE信息集成系统，该系统由可视化查询模块、结构化查询模块和数据库模块组成，该系统易于实现对先进设计和管理技术的支持，实现对分布式异构CAD与CAE应用系统支持下的产品进行虚拟设计，达到对内可支持并行工程的虚拟设计，对外可支持异地合作设计的目的。     

基于STEP的三维CAD和PDM系统集成方法研究

研究了基于STEP标准的产品信息模型、CAD数据交换接口、产品数据交换接口,提出了基于STEP中性机制和产品信息模型的三维CAD和PDM系统集成框架,该框架有助于实现广义CAD功能CAD/CAE/CAPP/CAM/CAQ/PDM/ERP之间的系统集成,异地、异构系统在企业间的集成,能够为企业设计和管理信息化提供一体化解决方案.     

基于层次结构的特征及其在CAD／CAM中的应用

特征的研究近年来得到长足的发展。然而由于特征的发展与人的思维和工程应用的背景相贯通，造成特征定义的不统一，因而限制了特征在ＣＡＤ／ＣＡＭ中应用，。使基于特征的ＣＡＤ／ＣＡＭ集成难以实现。文中把特征放在ＣＡＤ／ＣＡＭ集成的全局来考虑，不单单只是从特征的形状出发，而是同时从设计与加工两个角度出发来描述与定义特征。     

客户／服务器模型在模具CAD中的应用

在模具ＣＡＤ中应用客户／服务器模式的计算机结构，可以实现不同主机上不同进程的相互协作，共同完成大型复杂模具的设计任务，并使得模具ＣＡＤ系统具软硬件资源利用合理，设计效率高，并行性和集成性好的特点，文中还讨论了系统的结构配置，以及关键技术的实现方法。     

工业设计专业CAD课程设置与教学方法改革探索

计算机辅助设计是当前工业设计专业教学的重要内容,根据工业设计CAD课程教学的目标,针对当前课程设置和教学中的问题,提出了通过构建模块化CAD课程,将CAD教学贯穿到设计实践中,并采用连续性的教学进程来构建新的课程体系;在教学中采用突出思维方法的归类,注重CAD对设计要素的表达,以设计任务驱动的CAD学习等教学方法来提高学生利用计算机设计的能力和持续学习CAD的能力。     

Selecting and evaluating CAD systems

This article discusses some of the factors to be considered when selecting and evaluating systems for CAD (computer-aided design). An operative CAD system is one which performs a particular design function (application) by employing software running on suitable hardware.

Although the selection of an application of software and of hardware, are usually interdependant, they are treated separately within the article. The first two sections are concerned with identifying design problems which are suitable for the application of CAD. These sections are followed by a summary of the factors to be considered in choosing software and hardware. The final sections discuss the costing and economics of CAD systems.     

An effectiveness study of a CAD system augmented by audio feedback

The question addressed is the effectiveness of man-computer communication in computer-aided design (CAD). Many physical systems that design engineers develop on interactive CAD systems, in reality, produce noises that would give information about the system's performance.

The results of a controlled man-computer study are presented here. The task for the subjects was to design the acoustical treatment for a noisy laboratory. A control group worked in a conventional manner with the CAD system. The study group received continuous audio feedback indicative of the degree of noise reduction of their design. The statistically significant results are presented.     

A feasible approach to the integration of CAD and CAPP

Although current CAD systems are declared to be feature-based, in fact, the so-called feature is just a modeling macro or menu name such as Protrusion, Revolution, Cutout, Block, etc., instead of a design feature or manufacturing feature in accordance with engineering practice. Consequently, product model data insufficiency and incompatibility between varieties of application systems are still the major barriers to system integration, especially the integration of design and process planning. This paper proposes a practical solution for a bi-directional integration of CAD and CAPP on the platform of commercial CAD systems. The key techniques such as feature recognition and conversion, feature parameter and constraint extraction, feature tree reconstruction, technical information processing, process planning, automatic process drawing marking and 3D material stock CAD model generating are discussed. And the extracted features and their related technical information and knowledge are encapsulated together with the geometry-oriented CAD model to form an integrated product information model to facilitate effective integration with the downstream activities. The integrated CAD/CAPP system is implemented on a commercial CAD package, UGS/SolidEdge. A case study and industry implementation illustrate the feasibility of the approach proposed.     

A CAD-CAE integration approach using feature-based multi-resolution and multi-abstraction modelling techniques

In spite of the widespread use of CAD systems for design and CAE systems for analysis, the two processes are not well integrated because CAD and CAE models inherently use different types of geometric models and there currently exists no generic, unified model that allows both design and analysis information to be specified and shared. In this paper, a new approach called the CAD/CAE-integrated approach is proposed and implemented by a feature-based non-manifold modelling system. The system creates and manipulates a single master model containing different types of all of the geometric models required for CAD and CAE. Both a solid model (for CAD) and a non-manifold model (for CAE) are immediately extracted from the master model through a selection process. If a design change is required, the master model is modified by the feature modelling capabilities of the system. As a result, the design and analysis models are modified simultaneously and maintained consistently. This system also supports feature-based multi-resolution and multi-abstraction modelling capabilities providing the CAD model at different levels of detail and the CAE model at various levels of abstraction.     

GMCADS系统的研究及应用

当今,机械CAD向CAD/CAM/CAE集成化方向发展,机械系统运动学/动力学分析软件是集成化CAD/CAM/CAE不可缺少的支撑软件之一。我们以多刚体系统动力学为基本理论,研制了面向问题的、交互式的通用机械计算机辅助设计系统GMCADS。本文介绍了GMCADS系统的分析原理、图形输出技术,并给出了应用实例。     

支持合作过程的工程数据库设计事务模型

设计事务的管理是工程数据库管理系统的关键技术之一。