工程设计导论 Introduction to Engineering Design（PPT讲稿）工程设计与管理 Engineering Design & Management

ENGG 1100 Introduction to Engineering design Lecture 2: Engineering Design Management Helen Meng Professor and chairman Department of Systems Engineering Engineering Management hmmeng@se cuhk. edu. hk

ENGG 1100 Introduction to Engineering Design Lecture 2: Engineering Design & Management Helen Meng Professor and Chairman Department of Systems Engineering & Engineering Management hmmeng@se.cuhk.edu.hk 1

Engineer and Engineering Design The word engineer has Latin roots in ingeniare (i. e. to contr devise")and ingenium(i.e. cleverness") An engineer is a professional practitioner of engineering who has mathematical and scientific training and can apply such knowledge together with ingenuity to design and build complicated products, machines, structures or systems and thus develops solutions for technical problems An engineering design pulls together(i. e synthesizes) something new or arranges existing things in a new way to satisfy a recognized need of society. Engineering designs considers the limitations imposed by practicality, regulation safety, and cost

Engineer and Engineering Design • The word engineer has Latin roots in ingeniare (i.e. “to contrive, devise”) and ingenium (i.e. “cleverness”). • An engineer is a professional practitioner of engineering, who has mathematical and scientific training and can apply such knowledge, together with ingenuity, to design and build complicated products, machines, structures or systems and thus develops solutions for technical problems. • An engineering design pulls together (i.e. synthesizes) something new or arranges existing things in a new way to satisfy a recognized need of society. Engineering designs considers the limitations imposed by practicality, regulation, safety, and cost. 2

Design Discovery versus design Discovery is getting the first knowledge of something Design is the creation of new things SCience versus Engineering Science is knowledge based on observed facts and tested truths arranged in an orderly system that can be validated and communicated to other people Engineering_ is the creative application of scientific principles used to plan, build, direct, guide, manage, or work on systems to maintain and improve our daily lives Scientists versus engineers Scientists see things as they are and ask, WHY? Engineers see things as they could be and ask, WHY NOT?

Design • Discovery versus Design • Discovery is getting the first knowledge of something • Design is the creation of new things • Science versus Engineering • Science is knowledge based on observed facts and tested truths arranged in an orderly system that can be validated and communicated to other people. • Engineering is the creative application of scientific principles used to plan, build, direct, guide, manage, or work on systems to maintain and improve our daily lives • Scientists versus Engineers • Scientists see things as they are and ask, WHY? • Engineers see things as they could be and ask, WHY NOT? 3

Challenges of engineering design Creativity creation of something that has not existed before Complexity requires decisions on many variables and parameters Choice: requires making choices between many solutions at all levels from basic concepts to the smallest detail Compromise: requires balancing multiple and sometimes conflicting requirements

Challenges of Engineering Design • Creativity: creation of something that has not existed before • Complexity: requires decisions on many variables and parameters • Choice: requires making choices between many solutions at all levels, from basic concepts to the smallest detail • Compromise: requires balancing multiple and sometimes conflicting requirements 4

Importance of Engineering Design 100 808 Cost committed 惠8 oo8 eds 40 Cost incurred Tme〔 nonlinear) [Source: Dieter& Schmidt 2013

Importance of Engineering Design [Source: Dieter & Schmidt 2013] 5

Engineering Design Process Involves analysis and synthesis Analysis Decompose problem into manageable parts Calculate as much about the part's behavior as possible, using appropriate disciplines in science, engineering and computational tools before the part exists in physical form Synthesis Identification of the design elements that comprise the product, how it is decomposed into parts and the combination of the part solutions into a total workable system Requires Systems Thinking!

Engineering Design Process • Involves analysis and synthesis • Analysis – Decompose problem into manageable parts – Calculate as much about the part’s behavior as possible, using appropriate disciplines in science, engineering and computational tools, before the part exists in physical form • Synthesis – Identification of the design elements that comprise the product, how it is decomposed into parts and the combination of the part solutions into a total workable system • Requires Systems Thinking! 6

Iterative Engineering Design Process Complex systems can be decomposed into a sequence of design processes General information Source Asimov 1962 Specific information Design operation GOTO NO Evaluation YES THE Feedback loop NEXT STEP Iteration repeated trials Gives opportunity to improve design on basis of preceding outcome More knowledgeable team may arrive at acceptable solutions faster Requires high tolerance of failure Requires determination to persevere and work out the problem Often involve tradeoffs and arrive at near-optimal solutions

• Complex systems can be decomposed into a sequence of design processes • Iteration → repeated trials – Gives opportunity to improve design on basis of preceding outcome – More knowledgeable team may arrive at acceptable solutions faster – Requires high tolerance of failure – Requires determination to persevere and work out the problem – Often involve tradeoffs and arrive at near-optimal solutions Iterative Engineering Design Process [Source: Asimov 1962] 7

Problem-solving Methodology for Engineering Design 1. Defining the problem o Needs analysis, a difficult task o True problem not always what it seems at first o Requires iterative reworking as the problem is better understood o Problem statement must be as specific as possible 2. Gathering the information o Understand state of the art o Many sources of information, unstructured, unordered o Ask questions What do need to find out? Where can/find it? Howcan /getit? How credible and accurate is the information? How do /interpret the information formy specific need? When do i have enough information? What decisions resultfrom this information?

Problem-solving Methodology for Engineering Design 1. Defining the problem o Needs analysis, a difficult task o True problem not always what it seems at first o Requires iterative reworking as the problem is better understood o Problem statement must be as specific as possible 2. Gathering the information o Understand state of the art o Many sources of information, unstructured, unordered o Ask questions ▪ What do I need to find out? ▪ Where can I find it? ▪ How can I get it? ▪ How credible and accurate is the information? ▪ How do I interpret the information for my specific need? ▪ When do I have enough information? ▪ What decisions result from this information? 8

Problem-solving Methodology for Engineering Design(cont-1) 3. Generation for alternative solutions /design concepts o Use of creativity, simulation o apply scientific principles, use qualitative reasoning o Need to generate high-quality alternative solutions 4. Evaluation of alternatives and decision making o Selecting the best among several concepts o Often under incomplete information o May consider simulations o Very important> checking including mathematical check, engineering-sense checks(intuition) o Consider all conditions/situations(e.g. humdity vibration, temperature.in selecting"optimal"solution 5. Communication of the results o Oral /written communication o Engineering drawings, 3D computer models, software, etc

Problem-solving Methodology for Engineering Design (cont-1) 3. Generation for alternative solutions / design concepts o Use of creativity, simulation o Apply scientific principles, use qualitative reasoning o Need to generate high-quality alternative solutions 4. Evaluation of alternatives and decision making o Selecting the best among several concepts o Often under incomplete information o May consider simulations o Very important → checking, including mathematical check, engineering-sense checks (intuition) o Consider all conditions / situations (e.g. humdity, vibration, temperature…) in selecting “optimal” solution 5. Communication of the results o Oral / written communication, o Engineering drawings, 3D computer models, software, etc. 9

Problem-solving Methodology for Engineering Design(cont-2) ·| terative nature Back and forth among the 5 steps Understanding grows> evolve from preliminary to detailed design Define problem Gather Information Generate Alternative solutions Evaluate alternatives and make decision Communicate results

Problem-solving Methodology for Engineering Design (cont-2) • Iterative nature – Back and forth among the 5 steps – Understanding grows → evolve from preliminary to detailed design Define Problem Gather Information Generate Alternative Solutions Evaluate Alternatives and Make Decision Communicate Results 10