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.     

注塑件CAD建模与CAE智能处理的集成化研究

CAD／CAE技术的集成化研究是当前的一个研究热点，对于注塑件／模而言，CAD信息向CAE传输中存在信息丢失和少智能问题，而CAE的结果向CAD信息的反馈过程中也存在信息缺乏衔接和少智能化的问题，利用CBR（基于事件的推理）对工艺参数进行智能推理，然后结合推理出的参数值以及CAD中过滤出的信息，输入到CAE进行分析，对CAD中的特征信息与CAE后处理的信息进行合理的匹配，建立对后处理结果的缺陷解释专家系统。重点对工艺参数优选的CBR及后处理的专家解释系统和数据流的流动过程进行了深入的研究，提出CAD／CAE并行环思想，从而方便了注塑件特征造型与CAE智能处理的集成。     

HSC-1.1:A USEFUL TOOL FOR INJECTION MOLDING

An integrated CAD/CAE/CAM system, HSC--1.1, is described in the paper. HSC--1.1integrates surface modeling, mold design, technological simulations and NC machining into a full CAD/CAE/CAM system with data exchange from one module to another. The practice shows that HSC--1.1 is a useful tool for injection molding and can assist engineers in reducing mold cost and improvingmold quality.     

A novel CACD/CAD/CAE integrated design framework for fiber-reinforced plastic parts

This work presents a novel CACD/CAD/CAE integrated framework for design, modeling, and optimization of fiber-reinforced plastic parts, which can greatly enhance the current design practice by realizing partial automation and multi-stage optimization. To support this framework, a new heterogeneous feature model (HFM) has been developed to model the fiber-reinforced objects and to be transferred between engineering modules. To be specific, the CACD (computer-aided conceptual design) module employs the level-set structure and material optimization to produce the initial design with thickness control, and also the initial HFM; the CAD (computer-aided design) module allows manual editing on the HFM to reflect various design intents; then, the injection molding CAE (computer-aided engineering) simulates the manufacturing process, and the response surface method (RSM) is applied to optimize the process parameters of gate location, injection flow rate, mold temperature and melt temperature, to approach the manufactured fiber orientation distribution close to the optimized result produced by the CACD module; besides, the structural analysis CAE module generates the mechanical performance result to support the CACD module, as well as to validate the final design. By applying this framework, the final structural design including the fiber orientation distribution, will perform better in mechanical properties, and consume less matrix and fiber materials; besides, the design maturity can be approached in shorter time. To prove the effectiveness, a plastic gripper design will be comprehensively studied.     

基于CAD的注塑模具设计与仿真研究

研究了基于CAD技术的注塑模具设计流程,并对模具的工艺参数进行了分析和优化,具体采用CAD注塑模集成系统实现。完成了最优工艺参数方案的确定,通过UG的CAE分析模块的应用并以模拟结果为依据完成了对注塑件应力应变分布情况的分析,应力最大值及位置通过实验对比完成确定,为模具结构的优化方案提供参考。最佳注塑制品工艺参数通过分析相关工艺参数获取,并以音箱零件为例,对注塑模具型腔设计方法进行了探讨。     

基于模板的港口码头三维结构CAD/CAE 集成技术

针对港口码头结构CAD 几何模型生成CAE 单元模型,工程荷载CAD 模 型创建CAE 荷载模型,和CAE 分析结果与CAD 模型的关联关系等问题,利用模板的模型 独立性、规则性和可执行性等特性,研究了基于模板的港口码头三维结构CAD/CAE 集成技 术,定义了截面草图、三维实体和构件等多种CAD 建模模板,定义了机械草图和荷载等多 种荷载建模模板,定义了CAE 分析规则,实现了CAD 几何模型自动生成CAE 单元模型的 功能,定义了荷载转换规则,实现了工程荷载CAD 模型自动创建CAE 荷载模型的功能, 定义了整体模型模板,建立CAE 分析结果与CAD 模型的多对一关系,以此实现了港口码 头三维结构CAD/CAE 集成系统,大大提高了港口码头的设计效率,降低了设计人员的设计 难度,减少了设计错误。     

A CAD/CAE incorporate software framework using a unified representation architecture

Currently, there are still some big gaps between the CAD system and CAE system, e.g. the different data structure for model representation, which costs lots of time and effort of engineers in the interaction between these two kinds of systems. In order to bridge these gaps, an incorporate software framework is proposed in this paper. In this framework, the unified representation architecture (URA) is presented that makes CAD and CAE to be an organic entity. The URA contains three components: (1) unified data model (UDD) including unified B-rep, unified feature and unified mesh; (2) unified data management (UDM) consisting of unified interaction, unified data structure, unified Constructive Solid Geometry (CSG) history and unified interface; (3) unified display and post-processor (UDP) for both design and performance analysis. The URA facilitates the incorporation by explicitly representing design and analysis information as design features, which maintains their associations through the history chain. Besides the URA, a unified mesh data (UMD) is proposed to unify the mesh of CAD model display and CAE analysis with the purpose of reducing the redundancy of mesh data. The unified mesh data (UMD) is proposed to unify the mesh of CAD model display and CAE analysis, which greatly reduces the redundancy of mesh generation data. Finally, the high efficiency of the proposed framework is demonstrated by engineering examples.     

CAD与CAE集成过程的分析与建模

文章较详细地分析了CAD产品设计与CAE产品工程分析的集成过程,用 IDEF0对该 CAD设计和CAE工程分析的集成过程进行了建模,所建立的IDEF0模型是建立 CAD、CAE集成信息模型的基础。     

Development of Integrated Simulation System for Plastic Injection Molding

Numerical simulation of injection molding have had success in predicting the behavior of polymer melt in extremely complicated geometries. Most of the current numerical solutions are based on finite-element/finite-difference/boundary-element/volume-control methods and the surface model. This paper discusses the development of an integrated CAE system for injection molding in detail, and presents the mathematics for numerical simulation of filling, packing, cooling, stress and warpage in injection molding. The developed system named as HsCAE3D is introduced at the end.     

Hierarchical multi-layer CAD system for systematic design of complex logic controllers

Logic controllers play an extremely important role in the control of both continuous-time and discrete-time systems. However, the design process of logic controllers is not supported yet by a structured and integrated set of CAD/CAE tools for their specification, validation and interaction with the process. In addition, there is no consolidated standard in the international community. In this paper, a formalism is proposed, based on Petri nets, implementing a hierarchical/modular representation of logic controllers, suitable for the systematic development of complex programs; moreover, a theoretical and practical framework is established to formally verify the basic properties that a logic controller must possess. The developments illustrated here are especially effective in the perspective of design. The realization of a prototype CAD/CAE environment to design logic controllers is also described. Finally, an application example is developed and discussed.     

Numerical Simulation of Injection Molding Cooling Process Based on 3D Surface Model

The design of the cooling system of injection molds directly affects both productivity and the quality of the final part. Using the cooling process CAE system to instruct the mold design, the efficiency and quality of design can be improved greatly. At the same time, it is helpful to confirm the cooling system structure and optimize the process conditions. In this paper, the 3D surface model of mold cavity is used to replace the middle-plane model in the simulation by Boundary Element Metho…     

基于T-Spline的全自动几何拓扑修复方法

从高质量曲面网格生成的需求出发,提出了一种基于T-Spline的全自动几何拓扑修复方法.本文方法创新性主要可归纳为：1）对原有计算机辅助设计（Computer aided design,CAD）几何模型不进行任何修改保留其本真,自动识别CAD几何模型中常见不必要的几何特征,成功解决了CAD几何模型中存在的几何瑕疵,如短边、窄面、退化边、退化面、非连续光滑边界及尖锐特征等,利用新生成的"虚边"、"虚面"处理几何瑕疵,同时通过虚拓扑重构CAD几何模型的B-Rep;2）开发了一套CAD/CAE集成系统,统一了几何模型与计算分析模型,实现计算机辅助工程（Computer aided engineering,CAE）与CAD两者的无缝集成,所有拓扑修复操作及后续CAE分析计算均在同一环境下进行,避免了几何模型在CAE与CAD系统间进行转换时造成的数据丢失.该方法能够对复杂实体实现全自动几何拓扑修复及网格生成,实验表明,在保证不失真的前提下,修复后的几何模型能够生成质量良好的网格且能降低网格的生成规模,验证了本文方法的实用性和有效性,以满足工程实际分析的需要.     

基于注塑模CAD/CAE的自由曲面的裁剪

介绍一种基于离散曲面的裁剪算法,该算法适用于注塑模ＣＡＤ／ＣＡＥ或其它产品设计和有限元分析的领域,实践证明该算法自动化程度高、速度快、稳定可靠。     

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.     

Application of 3D Solid Modeling and Simulation Programs to a Bridge Structure

. This paper presents our work on the integrated use of computational methods (e.g. geometric modeling, simulation, visualization and optimization) for structural analysis and design. The focus in this paper is on 3D solid modeling and dynamic simulation. The paper describes our program system comprising the in-house program FEM90 integrated with commercial CAD and optimization programs. The program system is tested on a major bridge structure example. The example shows that 3D solid modeling and simulation are versatile tools for design of structures.     

Parametric CAD/CAE integration using a common data model

This paper proposes a CAD/CAE integration method using a “common data model” (CDM) containing all the required parametric information for both CAD modeling and CAE analysis. CDM is automatically generated by a knowledge embedded program code. The CDM is used as a parametric data model repository and the supply source of input for those associative entities of CAD and CAE models and thus maintaining the associative dependences among them. The structure as well as the data flow in the CDM is governed according to the general and widely used design processes. Thus designers can relate the expected scenarios with the engineering changes proposed and can take the parametric actions accordingly. CDM acts as the centralized parametric input for computer modeling software tools through their APIs. Throughout the design process the common data model gets modified during each development cycle according to designer’s intent, the changes in it are consistently reflected in both CAD and CAE models through regenerations and analysis iterations semi-automatically. The same data model in a suitable file format can be used to work with different CAD and CAE packages. As CDM, CAD and CAE work as different modules interconnected through a develop software prototype package which integrates APIs and knowledge rules embedded in the engineering procedures. However, each of the software tools used for each purpose can vary as per the original data requirement without hindering the process structure. The data model is reusable and the whole process is automated as far as possible so that the embedded expertise in the cycles of the adaptive design and manufacturing can be consistently applied iteratively during product development processes. Also being a data file in a suitable format generated via computer programming, the CDM is convenient to record and store information associated to all the product design revisions.     

An architecture for the vertical integration of tooling considerations from design to process planning

To meet the competitive demands of modern manufacturing, it is necessary to reduce design times and enrich decision making by integrating process planning into the design activity using Concurrent Engineering principles. Although this is traditionally done through the interaction between designers and process planners, it is perhaps more desirable for a CAD system to have the functionality necessary to automatically advise the designer of the shop floor implications of design decisions. Cutting tool selection is an essential thread linking feature-based design of machined parts to process planning. Thus, the implementation of tooling considerations into design is an important requirement for an integrated CAD/CAPP system. This paper defines an architecture to enable the vertical integration of tooling considerations from early design to process planning and scheduling. The architecture is based on a five-level tool selection procedure which is mapped to a time-phased aggregate, management and detailed process planning framework. This paper draws on literature and the results of an industrial survey to identify the tooling methods suitable for integration within a CAD system and categorises them into the five levels of tool selection. The functions are then placed on a time-dependent framework that covers the progression of a product from design to process planning. The new functionality is being implemented as an object-oriented application called VITool, which is being developed so that it can be fully integrated within an existing CAD system.     

甘蔗收获机械可视化虚拟设计平台的研究开发

介绍了甘蔗收获机械可视化虚拟集成设计平台研究开发的基本思路。该平台的构建通过STEP标准建立产品开发的全局共享信息模型，利用PDM软件集成和封装CAD／CAE及其它产品设计过程中用到的应用软件；平台也集成了甘蔗收获机械设计、分析和评价专家系统，专家系统采用模糊评价的方法对开发过程设计和仿真分析的结果进行评价和决策。集成平台支持甘蔗收获机械可视化虚拟产品集成化的团队设计及收获机械系列化产品开发。