EE/CpE322 Lecture 3. Bruce McNair Based on Engineering Design: A Project-Based Introduction (the 3 rd ed.), by C.L. Dym and P.

Transcription

1 EE/CpE322 Lecture 3 Bruce McNair Based on Engineering Design: A Project-Based Introduction (the 3 rd ed.), by C.L. Dym and P. Little

2 A Model of the Design Process

3 Stage 1: Problem Definition Input: Client s problem statement Tasks: Clarifying design objectives Establishing metrics for objectives Identifying constraints Revise client s problem statement Outputs: Revised problem statement List of final objectives Metrics for final objectives List of final constraints

4 Stage 2: Conceptual Design Inputs: Revised problem statement List of final objectives Metrics for final objectives List of final constraints Tasks: Establishing functions Establishing requirements (function specifications) Generating design alternatives Refining and applying metrics to design alternatives Choosing a design alternative Outputs: Requirements (function specifications) A chosen design

5 Stage 3: Preliminary Design Inputs: Requirements (function specifications) The chosen design Tasks: Modeling and analyzing the chosen design Testing and evaluating the chosen design Outputs: An analyzed, tested and evaluated design

6 Stage 4: Detailed Design Input: The analyzed, tested and evaluated design Tasks: Refining and optimizing the chosen design Assigning and fixing the design details and fabrication specifications Outputs: Proposed design and design details

7 Stage 5: Design Communication Input: The proposed design and design details Tasks: Documenting the final design details and fabrication specifications Documenting the design justification Outputs: Final Written and oral reports to client Description of the design process Drawings and design details Fabrication specifications

8 Feedback and Iteration

9 Source of Information Technical literature, handbooks Experts Heuristics (rules of thumb) Known physical relationships and models Codes (source and executables) Supplier s component specifications Competitive products Client s feedbacks Regulations Standards

10 Formal Design Methods Objectives trees Pairwise comparison charts Functional analysis Performance specifications Morphological charts Quality function deployment House of quality

11 Means of Accomplishing Tasks Literature reviews, Brainstorming, User surveys and questionnaires, Informal and structured interviews Focused groups Synectics (understand how creativity works) Benchmarking Reverse engineering Laboratory experiments Prototyping Proof of concept testing Computer models

12 Strategies in the Design Process Least commitment Premature commitment to a design or a configuration may lead to a suboptimal range of design choices Decomposition/divide and conquer Decomposing large problems into smaller subproblems Solutions to one subproblem should not violate the assumptions and constraints of complementary subproblem.

13 Managing the Design Process Project definition: determining what the client has in mind for the project Project framework: determining the specific tasks to be done, and organizing a team Project scheduling: assigning tasks and reaching agreement on when they must be accomplished. Project tracking, evaluation and control: monitoring the project to insure that deadlines are met, tasks accomplished, and resources used appropriately.

14 Strategies in Design Teams Team dynamics: Develop respect for the ideas and talents early in the process. Brainstorming: A formal technique for generating ideas and getting to know one another in a fun and respectful environment is brainstorming. Constructive conflict Conflicts are inevitable in design teams Constructive engagement to use the conflicts appropriately to generate ideas and understanding and to improve solutions.