机械工程导论第一讲

•
• • • • • • • • • •
presentation [,prezən'teiʃən, ,pri:-]n. 描述，陈述；介绍begins with a narrative
description of mechanical engineers and what they do (Chapter 1), and an outline of good problem-solving skills, particularly with respect to numerical values and unit systems (Chapter 2). Six elements of mechanical engineering are emphasized v强 调，着重（emphasize ['emfəsaiz]的过去式）subsequently in Chapter 3(Machine Components and Tools), Chapter 4 (Forces in Structure and Fluids), Chapter 5(Materials and Stresses), Chapter 6 (Thermal and Energy Systems), Chapter 7 (Motion of Machinery),and Chapter 8(Mechanical Design).Some of the applications that you will encounter [in'kauntə]n. vi. vt.遭遇，遇到along the way include internal combustion engines, rapid prototyping, computer-aided engineering, robotics, magnetic resonance imaging, jet engines, automatic transmissions, and solar power.
上述应用的实例,如内燃机，快速成型，计算机辅助工程，机器人学，
电磁超声成像，喷射发动机，自动变速箱，太阳能等。
--------------------------• • • • • • • • • • What should you be able to learn from this textbook? First and foremost, you will discover who mechanical engineers are, what they do, and what technologies they create. Section 1.3 details a “top ten” list of the profession‟s achievements. Take a look at it now for a glimpse of mechanical engineering technologies, and recognize how the profession has improved your day-to-day life and society in general. Second, you will learn some of the order-of-magnitude approximations [ə,prɔksi'meiʃən]n. [数] 近似法；接近；[数] 近似值and back-of-the-envelope calculations that mechanical engineers combine mathematics, science, computer-aided engineering tools, experience,
1 The Mechanical Engineering Profession
1.1
•
overview
Engineering is the practical endeavor in which the tools of mathematics and science are applied to develop working and cost-effective solutions to the technical problems facing our society. Engineers design many of the consumer products that you use every day and a large number of other products that you do not necessarily see but which are used in business and industrial setting. Engineers also design the machinery that is
APPROACH AND CONTENT
•
• • •
This textbook is intended for students who are in the first or second years of a typical
['tipikəl]college or university program in mechanical engineering or a closely related field. Throughout the following chapters, I have attempted to balance the treatments of problem-solving skills, design, engineering analysis, and practical technology. The
in part with the following „element‟:machine components, force, materials, energy,motion,and design. Mechanical
Student Preface
PURPOSE
• •
•
• • •
•
• • •
•
• • •
This textbook will introduce you to the field of mechanical engineering and help you appreciate how engineers design the hardware that builds and improve our society. As the title implies, this textbook is neither an encyclopedia [en,saikləu„pi:djə]n. 百科全书 nor a comprehensive [,kɔmpri'hensiv]adj. 综合的treatment of the discipline ['disiplin]n. vt. 训练 | 纪律 | 学科。Such a task is impossible for a single textbook, and, regardless, my perspective [pə'spektiv]n. 观点；远景；透视图adj. 透视的is that the traditional four-year engineering curriculum [kə'rikjuləm]n. 课程is just one of many steps taken during a lifelong education. By reading this textbook, you will discover the “forest” of mechanical engineering by examining a few of its big “trees”, and along the way you will be exposed to interesting and practical elements of the profession called mechanical engineering.
学生序
目的
• 这本教材将向你介绍机械工程领域，帮助你了解工程师们是如 • 何设计那些能够建造和促进我们社会进步的硬件。正如标题所 • 述，这本教材既不是百科全书，也不是本学科的综合训练。无 • 论如何，单一的一本教科书是无法完成这样的任务。我的观点 • 是，传统的四年机械工程学科的学习仅仅是所接受的终生教育 • 的一部分。学习这本书，你将通过了解几个机械工程的“大 • 树”，进而发现机械工程这个“森林”，由此，你将去探索机 械工 • 程中有趣的和实用的各个元素。
1 The Mechanical Engineering Profession
1.1 overviபைடு நூலகம்w
• -----------------------------------------------------------The discipline of mechanical engineering is concerned
方法和内容
•
这本书所针对的对象是那些正规学院或大学的大一或大二的机械工 程专业或者与之密切相关专业的学生。贯穿全书这些章节，我努力 平衡如下这四方面的关系，解决问题的技巧，设计，工程分析和实 践技能。全书以叙事的方式介绍什么是机械工程师，他们做什么工 作（第一章），以及一些好的解决问题技巧的概括。特别是注意数 值，和单位制（第二章）。机械工程的六种元素在后面几章依次强 调，第三章（机器零件和工具），第四章（结构和流体中的力）， 第五章（材料和应力），第六章（热量和能量系统），第七章（机 构的运动），第八章（机械设计）。在学习过程中，你会遇到一些
needed to manufacture those products,the factories that