浅谈计算机辅助工程(CAE)

浅谈计算机辅助工程

（CAE）

摘要

计算机辅助工程（CAE）是一种迅速发展的信息技术，是实现重大工程和工业产品的计算分析、模拟仿真与优化设计的工程软件，是支持工程科学家进行创新研究和工程师进行创新设计的、最重要的工具和手段。本文针对某微波通讯芯片的散热分析，详细介绍了运用I-DEAS ESC系统进行热分析的有限元建模方法与数值仿真过程，并与试验结果进行了对比。结果表明，所用方法正确，计算结果精确可靠。 关键词：电子系统冷却；数值仿真；I-DEAS 微波芯片

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目录

1绪论 ··································································································· 1

1.1 CAE技术概述 ····················································································· 1 1.2 CAE软件简介 ····················································································· 1 1.3 国外CAE技术概况 ·············································································· 2 1.4 我国CAE技术现状 ·············································································· 3 1.5本课题主要目的 ·················································································· 4

2 I-DEAS的有限元使用方法 ································································· 5

2.1 I-DEAS软件及有限元法概述 ································································· 5 2.2 I-DEAS进行有限元分析的基本过程 ························································ 6 2.3 I-DEAS热分析的建模理论 ··································································· 14 2.4 I-DEAS电子系统冷却模块（ESC） ························································· 15

3 I-DEAS 的热分析基础 ······································································ 17

3.1 热量传递的三种基本方式 ···································································· 17 3.2 一维稳态导热的理论计算 ···································································· 18 3.3 I-DEAS一维稳态导热分析 ··································································· 19 3.4 理论计算与I-DEAS计算结果对比 ·························································· 21

4基于I-DEAS ESC的微波芯片散热仿真 ··············································· 23

4.1 ESC热分析理论 ················································································· 23 4.2 微波芯片散热计算的有限元模型 ··························································· 23 4.3 计算结果与分析 ················································································ 25 4.4 结论 ·· ···························································································· 26

5总结与展望 ······················································································· 27 参考文献 ····························································································· 28 致谢 ····································································································· 29

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1 绪论

1.1 CAE技术概述

CAE(Computer Aided Engineering)是用计算机辅助求解复杂工程和产品结构强度、刚度、屈曲稳定性、动力响应、流体、热传导、三维多体接触、弹塑性等力学性能的分析计算以及结构性能的优化设计等问题的一种近似数值分析方法。

CAE从60年代初在工程上开始应用到今天，已经历了30多年的发展历史，其理论和算法都经历了从蓬勃发展到日趋成熟的过程，现已成为工程和产品结构分析中(如航空、航天、机械、土木结构等领域)必不可少的数值计算工具，同时也是分析连续力学各类问题的一种重要手段。随着计算机技术的普及和不断提高，CAE系统的功能和计算精度都有很大提高，各种基于产品数字建模的CAE系统应运而生，并已成为结构分析和结构优化的重要工具，同时也是计算机辅助4C系统(CAD/CAE/CAPP/CAM)的重要环节。

CAE系统的核心思想是结构的离散化，即将实际结构离散为有限数目的规则单元组合体，实际结构的物理性能可以通过对离散体进行分析，得出满足工程精度的近似结果来替代对实际结构的分析，这样可以解决很多实际工程需要解决而理论分析又无法解决的复杂问题。其基本过程是将一个形状复杂的连续体的求解区域分解为有限的形状简单的子区域，即将一个连续体简化为由有限个单元组合的等效组合体；通过将连续体离散化，把求解连续体的场变量(应力、位移、压力和温度等)问题简化为求解有限的单元节点上的场变量值。此时得到的基本方程是一个代数方程组，而不是原来描述真实连续体场变量的微分方程组。求解后得到近似的数值解，其近似程度取决于所采用的单元类型、数量以及对单元的插值函数。根据经验，CAE各阶段所用的时间为：40%～45%用于模型的建立和数据输入，50%～55%用于分析结果的判读和评定，而真正的分析计算时间只占5%左右。针对这种情况，采用CAD技术来建立CAE的几何模型和物理模型，完成分析数据的输入，通常称此过程为CAE的前处理。同样，CAE的结果也需要用CAD技术生成形象的图形输出，如生成位移图、应力、温度、压力分布的等值线图，表示应力、温度、压力分布的彩色明暗图。我们称这一过程为CAE的后处理。针对不同的应用，也可用CAE仿真模拟零件、部件、装置(整机)乃至生产线、工厂的运动和运行状态。

1.2 CAE软件简介

CAE软件可以分为两类：针对特定类型的工程或产品所开发的用于产品性能分析、预测和优化的软件，称之为专用CAE软件，如：专用的流体分析软件—STAR

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