计算机英语(第三版)1010.2作者：刘兆毓、郑家农(普通高等教育“十一五”国家级规划教材).ppt

PART ⅢAPPLICATIONSCHAPTER 10CAD/CAM/CAE /CIM AND MRP-Ⅱ10. 2COMPUTER APPLICATIONCHAPTER 10-110.2 COMPUTER APPLICATIONMAIN POINT Main point:lHow the computer, or CAD, CAM, and CAE technologies, are employed in the product cyclelVirtual prototypinglThe activities involved in the manufacturing processText1 We have described a typical product cycle. Now we will review it to show how the computer, or CAD, CAM, and CAE technologies, are employed in the cycle. As indicated earlier, the computer is not widely used in the synthesis phase of the design process because the computer does not handle qualitative information well. However, in the synthesis subprocess, for example, a designer might well collect the relevant design information for the feasibility study by using a commercial database and collect catalog information in the same way. 宾语从句 条件状语从句Text2 Nor is it easy to imagine how a computer might be used in the design conceptualization phase because the computer is not yet a powerful tool for the intellectual creative process［1］. The computer may contribute in this phase by physically generating various conceptual designs efficiently ［2］. The parametric modeling or macroprogramming capability of computer-aided drafting or geometric modeling may be useful for this task. These packages are typical examples of CAD software. 否定 主谓倒装 条件状语从句Text3You may imagine a geometric modeling system to be a three-dimensional equivalent of a drafting system; that is, it is a software package by which a three-dimensional shape instead of a two-dimensional picture is manipulated. Question1: What are typical examples of CAD software?? 表语从句 定语从句Text4 The analysis subprocess of the design process is the area where the computer reveals its value. In fact, there are many available software packages for stress analysis, interference checking, and kinematic analysis. These software packages are classified as CAE. One problem with using them is the provision of the analysis model. It would not be a problem at all if the analysis model were derived automatically from the conceptual design. However, as explained previously, the analysis model is not the same as the conceptual design but is derived by eliminating unnecessary details from the design or by reducing its dimensions. 定语从句 条件状语从句并列Text5Question2: How to create the abstract shape of the design ? The proper level of abstraction differs, depending on the type of analysis and the desired accuracy of the solution. Thus it is difficult to automate this abstraction process; accordingly the analysis model is often created separately. It is a common practice to create the abstract shape of the design redundantly by using a computer-aided drafting system or a geometric modeling system or sometimes by using the built-in capability of the analysis packages. Text6 The analysis subprocess can be imbedded in the optimization iteration to yield the optimal design. Various algorithms for finding the optimal solution have been developed, and many optimization procedures are commercially available. Optimization procedures could be thought of as a component of CAD software, but it is more natural to treat optimization procedures separately. The design evaluation phase also can be facilitated by use of the computer. If we need a design prototype for the design evaluation, we can construct a prototype of the given design by using software packages that automatically generate the program that drives the rapid prototyping machine［3］. 条件状语从句定语从句定语从句Text7Question3: What is the relationship between optimization and CAD ? These packages are classified as CAM software. Of course, the shape of the prototype to be made should exist in advance in a type of data. The data corresponding to the shape are created by geometric modeling. Even though the prototype can be constructed conveniently with rapid prototyping, it would be even better if we could use a virtual prototype, often called digital mock-up, which provides the same valuable information［4］. 让步状语从句 条件状语从句 定语从句Text8 As the analysis tools used to evaluate the digital mock-up become powerful enough to give an analysis result as accurate as that from the equivalent experiment on a real prototype［5］, digital mock-ups will tend to replace real prototypes. This tendency will increase as virtual reality technology enables us to get the same feeling from the digital mock-up as we get from the real prototype. The activity of building digital mock-ups is called virtual prototyping. The virtual prototype can also be generated by a kind of geometric modeling that is specialized for that purpose. 时间状语从句 比较状语 时间状语从句 方式状语从句 定语从句Text9Question4: What is virtual prototyping ? The final phase of the design process is design documentation. In this phase, computer-aided drafting is a powerful tool. The file-handling capability of computer drafting systems also allows the systematic storage and retrieval of documents. Computer technologies are also used in the manufacturing process. Text10The manufacturing process includes the activities of production planning, design and procurement of new tools, ordering materials, NC programming, quality control, and packaging, as illustrated in Fig.10-1, so all the computer technologies for these activities can be classified as CAM. For example, computer-aided process planning (CAPP) software to aid the process planning activity is one type of CAM software. As mentioned previously, process planning is difficult to automate, and thus 100 percent automatic CAPP software is not available currently. However, there are many good software packages that generate the numerically controlled (NC) programs that drive NC machines. 定语从句 条件状语从句Text11Question5: Describing the activities in the manufacturing process ? This type of machine creates a given shape when the shape exists in the computer in the form of data. This is similar to driving the rapid prototyping machine. In addition, also belonging to CAM are the software packages to program robot motion to assemble components or deliver them to the various manufacturing activities, or to program a coordinate measuring machine (CMM) to inspect the product［6］. 时间状语从句 [1] 将否定词nor提至句首强调否定意义时，要求主谓倒装； because引导一个原因状语从句。

[2]in this phrase 在这一阶段；conceptual designs 概念化设计 [3] If 引导一个条件状语从句,we can…为主句by using…为方式状语，第一个that 引导定语从句修饰packages, 第二个that引导定语从句修饰program [4]even though引导让步状语从句,it would be…为主句，if…为条件状语从句often called…过去分词短语作定语修饰prototype,which引导定语从句亦修饰prototype [5]As the analysis…是一个状语从句， 其中又包含由as…as…引导的同等比较状语从句 [6] 倒装句，既强调also belonging to CAM, 又使长主语便于展开正常语句应该是the software packages…are belonging to CAMNOTESNOTESinterference checking 干扰检验kinematic analysis 运动分析iteration 迭代 virtual prototype 虚拟原型NC (Numerical Control) 数控 CAPP (computer-aided process planning) 计算机辅助工艺计划CMM (coordinate measuring machine) 三坐标测量机 KEYWORDSKEYWORDSEXERCISES1 EXERCISES 1.To fill in the blanks.(1) The computer is not widely used in the synthesis phase of the design process because the computer does not handle information well.(2) Nor is it easy to imagine how a computer might be used in the design conceptualization phase because the computer is not yet a powerful tool for the creative process.(3) It would not be a problem at all if the analysis were derived automatically from the conceptual design.(4) The analysis subprocess can be embedded in the optimization iteration to yield the .qualitativeintellectualmoleloptimal design(5) If we need a design prototype for the design evaluation, we can construct a of the given design by using software packages that automatically generate the program that drives the rapid prototyping machine.(6) The final phase of the design process is design .(7) Computer-aided process planning software to aid the process planning activity is one type of software.(8) Process planning is difficult to automate, and thus 100 percent automatic software is not available currently. E EX XE ER RC CI IS SE ES S2 2CAPPCAMdocumentationprototype。