EML4550, Spring 2009 1

EML4550 – Engineering Design Methods (2009)

Introduction to Design

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Engineering as a Profession

Profession Definition (from Wikipedia): an occupation, vocation or career

where specialized knowledge of a subject, field, or science is applied. It is usually applied to occupations that involve prolonged academic training and a formal qualification. It is axiomatic that "professional activity involves systematic knowledge and proficiency." Professions are usually regulated by professional bodies that may set examinations of competence, act as a licensing authority for practitioners, and enforce adherence to an ethical code of practice

Required Attributes (ABET accreditation process) Specialized knowledge Intensive preparation Organizational structure High standard, continued study, and public service

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ABET Outcome Criteria

Engineering programs must demonstrate that their students attain abilities to:

(a) to apply knowledge of mathematics, science, and engineering

(b) design and conduct experiments, as well as to analyze and interpret data

(e) identify, formulate, and solve engineering problems(k) use the techniques, skills, and modern engineering

tools necessary for engineering practice.

-- These are more traditional engineering science subjects

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ABET Outcome Criteria (cont.)

Engineering programs must demonstrate that their students attain abilities to:

(c) design and conduct experiments, as well as to analyze and interpret data

(c) to design a system, component, or process to meet desired needs within realistic constraints such as economic, environmental, social, political, ethical, health and safety, manufacturability, and sustainability

(d) function on multi-disciplinary teams(g) communicate effectively

-- These are design-emphasis curriculum

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ABET Outcome Criteria (cont.)

Engineering programs must demonstrate that their students attain abilities to:

(f) understanding of professional and ethical responsibility

(h) the broad education necessary to understand the impact of engineering solutions in a global, economic, environmental, and societal context

(i) recognize of the need for, and an ability to engage in life-long learning

(j) a knowledge of contemporary issues

-- These are broad-based educational components

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Professional Components

(a) one year of a combination of college level mathematics and basic sciences (some with experimental experience)

(b) one and one-half years of engineering topics, consisting of engineering sciences and engineering design, providing a bridge between mathematics and basic sciences on the one hand and engineering practice on the other.

(c) a general education component that complements the technical content of the curriculum and is consistent with the program and institution objectives.

Students must be prepared for engineering practice through the curriculum culminating in a major design experience based on the knowledge and skills acquired in earlier course work and incorporating appropriate engineering standards and multiple realistic constraints. (--Capstone Experience)

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Engineering Design

Engineering design is the systematic, intelligent generation and evaluation of specifications for artifacts whose form and function achieve stated objectives and satisfy specified constraints

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Engineering Design (ABET)

Design is the process of devising a system, component, or process to meet desired needs. It is a decision-making process (oftentimes iterative) in which mathematics, the basic sciences, and the engineering sciences, are applied to convert resources optimally to meet a certain objective.

Among the fundamental elements of the design process are the establishment of objectives and criteria, synthesis, analysis, construction, testing, and evaluation

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Engineering Design - Key Words

Systematic – “orderly”, “with planning” and “methodical”

Process – not an isolated action but ongoing activity Generation and evaluation - Trade-offs, optimization Specifications - What will it do, how it will do it,

drawings, manufacturing methods, etc. Artifacts - Physical objects Form and function - “Shape” and “Operation” (form

follows function? Function follows form?) Stated objectives - Specified needs or problem Constraints - Budget, environment, etc.

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Other aspects of the design process

Formal process - yes Informal (social) process - yes

Design takes place in social setting. emotions, negotiations, personal dynamics, are all part of the process and affect the outcome as much as the formal components

Management and teamwork are an integral part of every design effort

Alternate Definition of Design (Luongo, 2001) : A form of art (creativity) in which the scientific disciplines (tools) are used to arrive at an optimal solution (painting) on a pre-specified problem (canvas) brought up by a customer (viewer)

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It takes three to design a product

Designer User

Client

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Examples

A new line of rollerblades• User - Anonymous crowd of teenagers• Client - Marketing Department of Company ABC• Designer - Engineering + Manufacturing Departments of Company

ABC

An airport• User - Airlines and passengers• Client - A municipality• Designer - Engineering company (civil)

A refinery• User - Oil company• Client - Oil company• Designer - Engineering company (chemical and mechanical)

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Product design is multi-disciplinary

Marketing Market research, product opportunities Users perspective, pricing

Accounting/Finance Budget and contract negotiation

Engineering Product specification and definition Detailed design and implementation

Manufacturing Production process design and start-up Distribution

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The design-manufacturing cycle

EngineeringDesign

Manufacturing

Design cannot be separated from manufacturing Manufacturing constraints must be ‘built into’ design Manufacturing ‘lessons’ must be introduced to future products From idea-to-design-to-drawing-to-prototype-to-product

seamlessly

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The challenges of product design

Trade-offs Understand trade-offs Decision-making under uncertainty Sub-optimum choice

Dynamics Shifting market and requirements Competition

Details Constant decision-making Record-keeping

Time pressure

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The rewards of product design

Creation From artist to engineer to businessman Witness a ‘birthing experience’

Societal impact Fulfill real needs of real people Long-lasting effects of personal work

Diversity People diversity Task diversity Life-long learning

Team spirit Friendship and support

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The phases of product design

1. Conceptual Development2. System-level Design3. Detailed Design4. Testing and Refinement5. Production Ramp-up and Delivery

1 2 3 4 5

Production development process

Cost spend

Cost planned

Cost Effective

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A Model of the Engineering Design ProcessHyman, Chapter 1

1. Recognizing the need2. Defining the problem3. Planning the project4. Gathering information5. Conceptualizing alternative approaches6. Evaluating the alternatives (analyzing)7. Selecting the best alternative8. Communicating design9. Implementing the preferred design

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Product design process

Phases: Conceptual Development System-level Design Detailed Design Testing and Refinement Production Ramp-up and

Delivery

Steps: Identify customer needs (1) Establish product

specifications (2, 3, 4) Concept generation (5) Concept selection (6,7) Product architecture (9) Design for manufacturing

(detailed design) (9)

Note: (#) indicates corresponding step # used in the alternative model (Hyman) to be presented later

Step (8), communication, is used throughout

Permeating the Process:- Economics- Management and Control

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Hyman, “Engineering Design”, book organization

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Design process is highly iterative

Often revisit a certain step in different phases of the process

Continuous evaluation of options (analysis) for each component or sub-system

Constant evaluation of the impact on overall system of design choices

When does the design process end? When are we done?

When the cost of further design effort is not justified by the gains from an optimized design, or when we run out of time (or money) provided that the design is already sound