管类钣金件参数化设计与展开系统的开发与实现

在分析国内外钣金行业计算机辅助设计状况和生产需求的基础上,开发了管类钣金件参数化设计与展开系统。该系统集构件设计与展开功能于一体,所包含的设计对象全面,设计结果准确,使用方便。介绍了系统开发中的构型策略、接口曲线求取、接口曲线向中性层曲面的映射和界面设计等关键技术。举例说明了系统的应用方法。     

CAD/CAM技术在机车车辆钣金件展开放样中的应用

对形状复杂的钣金件展开,可通过可展曲面的几何尺寸,用人工通过一系列重复性解析计算求得展开图的尺寸,但工作量大,且难以保证结果的准确性.用CAD/CAM:进行辅助展开放样,既无需现场放样,又不用建立数学模型,就能对复杂构件作更精确的展开放样.     

立锥式粉料运输罐体曲面展开及CAD系统开发

分析了专用罐体的几何特征及设计要求,以三角形近似展开直纹面方法为主、结合母线长度不变原则,近似展开了外锥面和内锥面等不可展曲面及筒体表面,形成一套专用罐体的曲面落料加工设计方法.基于罐体曲面离散化,用四面体离散法近似计算锥体容积.通过与罐体的Pro/Engineer实体模型数据对比,验证了曲面近似展开和容积近似计算的数值精度和可靠性.用Matlab和Visual C 联合编程开发了罐体参数化CAD系统,用于罐体结构设计.     

Q345 中厚板 V 形折弯应力 应变分析

目的研究Q345中厚板在V形折弯时的应力应变中性层内移规律。方法通过对中厚板135°折弯过程进行数值模拟,分析了板料在成形过程中的等效应力应变及其中性层内移现象,测得了应变中性层与几何中间层之间的距离变化。在此基础上,采用厚度为16 mm的Q345板料进行物理实验,并与模拟结果进行了对比分析。结果在成形过程中,等效应力应变中性层均产生了内移现象,且应力中性层的内移量明显大于应变中性层的内移量;成形结束之后,应变中性层与几何中间层的距离为3.3 mm;实验结果显示,应变中性层的内移量为3.1 mm左右,与模拟值较为一致。结论数值模拟方法可以为应力应变中性层计算提供指导。对于中厚板折弯,采用几何中间层展开求得的坯料尺寸并不准确。     

回转曲面近似展开的数学模型

通过对不可展回转曲面近似展开方法的研究,得到了回转曲面近似展开,精度分析和误差矫正的数学模型。在回转曲面构件的金属加工中,该模型可作为展开样板计算机辅助设计与 基本算法。     

管类钣金结构接口几何信息的分析与提取

在分析国内钣金行业生产需求的基础上,研究管类钣金结构接口的板厚处理,提出了接口几何信息提取的原理、方法和步骤,从图解、解析建模和基于数值方法的系统开发等几方面,实现了接口几何信息的精确提取和厚板构件准确的板厚处理,其思想方法和步骤具有一定的通用性,研究结果对于提高管类钣金结构的产品质量、降低生产成本具有应用价值。     

曲面片的可展切曲面及其映射分析

论文以微分几何可展曲面理论为基础,提出了过曲面曲线构造其可展切曲面的方法,得出了可展切曲面的表达形式,对可展切曲面进行了分类,通过建立两曲面间的映射关系,实现了它们间整体与局部的映射分析,较准确地把握曲面的变形情况,并通过实例对方法进行了验证.曲面片可展切曲面的方法可以应用于曲面设计、曲面近似展开和纹理映射等方面.     

布绒玩具带有省道的曲面展开算法

 三维布片的平面展开是布绒玩具CAD系统开发中两个最大技术难点之一，根据文献检索，至今还没有具备布绒玩具三维曲面展开功能的商品化软件问世。采用弹簧-质点模型，通过优化算法实现了布绒玩具的三维曲面展开，对优化过程中的几何约束采用图形处理的方法加以解决，取得了预期的展开效果。     

自由曲面最佳展开基点的几何属性

在分析自由曲面一般展开方法的基础上,提出了近似展开样板误差的评价方法。证实了展开基点对曲面近似展开结果具有较大的影响,并证明了最佳展开基点位置存在的客观性。进而利用等误差曲线的生成,实现了曲面片最佳展开基点位置的可视化,通过实验,得出了最佳展开基点位置与曲面片几何属性间的关系。最后通过曲面片的近似展开,验证了所得结论的正确性,也给出了最佳展开基点的搜索方法。     

论切向接管CAD三维建模展开放样中的应用

展开放样就是在不改变构件表面积的情况下,将其依次摊开在一个平面上。展开可分为可展曲面的表面展开和不可展曲面的近似展开两种。构件表面展开的方法一般有作图法、计算法、系数法等。这三种方法在结构工程中应用相当广泛,是实践工程经验的积累,要求工程技术人员必须掌握的。用CAD三维建模功能进行展开放样,从原理上与传统展开放样方法截然不同,不需要研究投影关系和技巧,便可获得展开数据。     

基于NX平台的级进模工艺自动化设计中的关键技术与软件系统研发

目的 开发一套基于NX平台的自动化级进模工艺设计系统,提升工艺设计的自动化水平.方法 基于工艺结构一体化的思想,采用自动化特征识别、工具体记忆特征和折弯中性层展开等技术,实现自动化的工艺设计.结果 在NX7.5平台上,以格力空调外机右侧板为例进行测试,完成工艺设计大约耗时10 min左右,生成的工艺信息可以用于后续的模板模架生成、冲头调用和标准件排配等模块,实现了自动化的结构设计.结论 基于特征识别等技术研发的自动化工艺设计系统,显著提高了设计效率,缩短了模具设计周期.     

弯曲件毛坯的CAD软件开发

介绍了一种采用Ｃ语言开发的一套集弯曲件自动展开，图形快速绘制和尺寸标注于一体的弯曲件毛坯ＣＡＤ软件，该软件对各个弯曲面采用相对坐标分块的计算的方式进行展开，方便灵活。通过使用计算标准齐全的数据库系统可使弯曲件的展开计算结果快速准确。该软件还可以用于不带弯曲线的平板零件的ＣＡＤ工作。     

基于数据库的机床卡盘参数化零件设计系统的实现

介绍了ＡｕｔｏＣＡＤＦｏｒＷｉｎｄｏｗ下,一种基于数据库的卡盘参数化零件设计方法,分析了Ｆｏｘ系列数据库／表的结构,了用Ｃ语言进行参数化零件设计,ＡｕｔｏＣＡＤ的界面设计,以及Ｆｏｘ系列数据库的C语言操作通用接口设计的方法.     

BUMS—Bonner sphere Unfolding Made Simple: an HTML based multisphere neutron spectrometer unfolding package

A new multisphere neutron spectrometer unfolding package, Bonner sphere Unfolding Made Simple (BUMS) has been developed that uses an HTML interface to simplify data input and code execution for the novice and the advanced user. This new unfolding package combines the unfolding algorithms contained in other popular unfolding codes under one easy to use interface. The interface makes use of web browsing software to provide a graphical user interface to the unfolding algorithms.BUMS integrates the SPUNIT, BON, MAXIET, and SAND-II unfolding algorithms into a single package. This package also includes a library of 14 response matrices, 58 starting spectra, and 24 dose and detector responses. BUMS has several improvements beyond the addition of unfolding algorithms. It has the ability to search for the most appropriate starting spectra. Also, plots of the unfolded neutron spectra are automatically generated.The BUMS package runs via a web server and may be accessed by any computer with access to the Internet at http://nukeisit.gatech.edu/bums.     

Multidisciplinary design methodology for mechatronic systems based on interface model

Mechatronic system is considered as the resulting integration of electrical/electronic system, mechanical parts and information processing. Therefore, to enable a systematic design process of mechatronic systems with a high-level integration, the so-called multidisciplinary integrated design is required. However, neither academia nor industry has yet provided an effective solution, which can fully support the whole design process to achieve such multidisciplinary integrated design. In order to organise the design activities from different disciplines and to aid the designers to achieve the multidisciplinary integrated design, the authors propose a design methodology based on a multidisciplinary interface model. In line with the systems engineering practices, an extended V-model is used as the macro-level process in the proposed design methodology. It starts with identification of requirements on the entire system and ends with a user-validated system. The hierarchical design model is adopted as the micro-level process. It supports the specific design phases where individual designers can structure design sub-tasks and proceed and react in unforeseen situations. To ensure the consistency and traceability between the two levels, the multidisciplinary interface model is proposed. This design methodology is demonstrated by studying the design process of a quadrotor.     

从CAD／CAPP集成看轴类零件的产品模型合理表示

本课题组在开发CIMS特征造型软件过程中试作了CAD与CAPP的直接接口,从中发现CAD与CAPP对于零件的特征建模表示方法有不同的理解和要求。本文列举这些差异,以供CIMS和并行工程环境下建立更完善的集成产品信息模型作参考。     

基于Pro/E的货车转向架参数化设计系统的研究

将参数化设计技术应用于货车转向架的设计,通过设计参数来驱动转向架零部件的几何模型,简化生成和修改零部件模型的操作。在现有计算机辅助设计软件的基础上,运用其二次开发工具、面向对象的程序设计语言、数据库技术及其编程接口进行二次开发,实现了基于参数化设计技术的货车转向架设计系统,提高了货车转向架设计的速度和质量。     

汽车零部件包装数据智能管理系统的开发与应用

目的 为实现汽车零部件包装设计高效化、包装管理精益化及数据化,开发一套零部件包装数据智能管理系统。方法 在对零部件包装设计及包装方案管理现状进行分析的基础上,明确系统的开发目标,即包装方案的数据化、BOM化、版本化以及标准化,并基于创建包装视图、重构零部件存储库、搭建相似包装方案重用逻辑、分类存储包装文档等方法,开发智能管理系统,并打通该系统与采购系统、工艺系统的数据接口,实现全流程数据交互。结果 系统上线后,零部件包装数据管理水平得到了有效提升。结论 所述包装数据管理系统作为支持企业迈向智能制造的底层数据管理方式是有效可行的。     

Evaluation of virtual reality interface for product shape designs

It is generally acknowledged that existing computer-aided design systems have inefficient user interfaces. Especially during the concept shape design stage, these systems prove to be cumbersome because of two reasons: (i) they require the usage of two-dimensional (2D) input devices, while the designs are typically three-dimensional (3D); and, (ii) CAD systems require the specification of dimensions, which may not be precisely known at the concept stage. To overcome these limitations, this research proposes the use of virtual reality (VR) devices to provide a physically intuitive interface for concept shape creation. The intuitiveness of the interface arises from the use of natural hand gestures and voice commands that emulate the way in which designers discuss concept shapes. In this scenario, the interface between the human and computer plays a central role with respect to usability, usefulness and accuracy. The focus of this research is on using two modalities: (i) hand input; and, (ii) voice driven commands, or a combination of these modalities to accomplish typical CAD tasks. Based on experience with a conventional CAD system, a set of typical CAD tasks are identified. A series of tests are then performed to determine the relative efficiency of the different modality combinations to achieve each task. The interface test results indicate that while voice commands are intuitive in initiating operations such as viewpoint zooming in/out and object creation/deletion, hand inputs are effective in performing spatial tasks such as interactive dimensioning and re-location of shapes. It was also found that a combination of voice and hand input can be used for accomplishing certain tasks more effectively such as, zooming in/out a particular direction (hand orientation indicates direction and voice is used for indicating zoom in/out operation). Based on the experience with the prototypical system developed it is concluded that voice and hand input are effective ways of building three-dimensional shapes in a virtual reality environment. To verify the efficiency of the VR-CAD interface, sample injection molded parts are built on the current VR-based CAD system and a traditional CAD system, and the times taken to build these parts are compared. The test results indicate that building geometry shapes containing canonical forms, such as block, cylinder, sphere, ⃛ etc, using a VR interface results in a speedup of five to ten times over traditional CAD systems.