ENGR 107: Engineering Fundamentals

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ENGR 107 Engineering Fundamentals

• Lecture 4
• The Engineering Design Process
• The Engineering Method and Problem Solving
  Process
• C. Schaefer
• September 16, 2002

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Assignment

• Read Chapter 2 of the textbook.
• Group Cost ROMs, Bills of Material, and list of
  required tools are due today to the Systems
  Engineering Group.
• Systems Engineering group preliminary schedule
  and budget due on Wednesday.
• Groups review hull and keel construction.

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The Engineering Method

• A process within a process.
• Systems engineering process.
• Engineering method.
• The engineering method is the formal approach an
  engineer takes to solve a particular problem.
• The engineering method is a thought process or
  approach similar to, though not identical to, the
  scientific method.

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The Engineering Method1

• Information gathering.
• Experimentation.
• Synthesis.
• Evaluation and testing.
• Presentation of solution.

• Identification of problem.
• Analysis.
• Transformation.
• Alternative solutions.
• Modeling.

1Engineering An Introduction to a Creative
Profession, G.C. Beakley, D.L. Evans, J.B. Keats
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The Engineering Method2

• Recognize and Understand the Problem.
• Accumulate Data and Verify Accuracy.
• Select the Appropriate Theory or Principle.
• Make Necessary Assumptions.
• Solve the Problem.
• Verify and Check Results.

2Engineering Fundamentals and Problem
Solving, A.R. Eide, R.D. Jenison, L.H. Mashaw,
L.L. Northrup
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The Engineering Method3

• Identify and define the problem.
• Research the problem
• Accumulate data.
• Relevant theory.
• Previous solutions and approaches.
• Solve the problem
• Develop alternatives.
• Modeling/simulation.
• Experimentation
• Synthesis
• Testing and verification.
• Presentation.

The engineering method is a continuous
feedback loop.
3 My general method of solving engineering
problems. The Schaefer Method.
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The Problem With These Approaches?

• They are predominantly analytical with no
  explicit creative process.
• Problem solving consists of two elements
• Creative
• Analytic
• Much emphasis in academia and industry on
  analytical methods almost at the exclusion of
  creative processes.

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Analytic and Creative Problem Solving1

• Identify the problem.
• Define the working criteria or goals.
• Research and gather data.
• Brainstorm for creative ideas.
• Analyze.
• Develop models and test.
• Make the decision.
• Communicate and specify.
• Implement and commercialize.
• Prepare post-implementation review and assessment.

1Oakes, et al
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Contrast with Scientific Method

• Define the problem.
• Gather the facts.
• Develop a hypothesis.
• Perform a test.
• Evaluate the results.
• Notice that science is not overly concerned with
  implementation, only knowledge gathering.

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Lets Look at an Example

• Simplified real world example SUV anti-lock
  braking system (ABS).

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Sport Utility Vehicle (SUV) Anti-Lock Braking
System (ABS)
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Identification of Problem

• What is required?
• What must be done and why?
• Scope of problem define problem boundaries.
• Example Anti-lock Braking System
• Is it possible to successfully retrofit an ABS
  developed for compact cars to heavier, sports
  utility vehicles?

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Research the Problem

• Can we decompose the problem into easily managed
  subproblems?
• This step defines, for example
• Literature review for similar problems and
  solutions to those problems.
• Relevant analytical and modeling techniques.
• Testing requirements.
• Design constraints.
• Resource requirements and allocation.
• Project schedule.

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Research ABS Example

• Literature search Internet search on ABS.
• Constraints (example)
• Retain compact car ABS system architecture.
• SUV ABS costs cannot exceed 110 of current
  compact car ABS system cost.
• Time to market 3 months.
• Performance criteria
• SUV Total Time to Stop ? 15 increase over
  compact car.
• SUV Wheel Lock Skid Time ? 10 increase over
  compact car.
• Approach
• Develop MATLAB model of ABS system.
• Parametric analysis using model.
• Modify system constants.

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Solve the Problem

• Develop alternatives. For example
• Hardware and software design alternatives.
• List of independent variables to vary in modeling
  or simulation.
• Modeling
• Conceptual models.
• Physical models and engineering mockups.
• Graphical models.
• Mathematical models.
• Computer models.

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Solve the Problem

• Experimentation
• Computer simulation.
• Testing, for example
• Ground tests.
• Flight testing.
• Synthesis
• Subproblem solutions are merged.
• E.g., manufacturing and engineering resolving
  issues associated with manufacturability.

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Solve Problem ABS Example

• ABS hardware and system architecture fixed with
  exception of interface to SUV.
• Control software can be modified.
• Matlab simulation.
• Skid pad testing to verify simulation results.
• Presentation of results to Product Development
  Team.

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ABS Braking Simulation Model
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Simulation Results
Vehicle Weight 1600lbs Hydraulic Lag 0.01 sec
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Simulation Results
Vehicle Weight 2900 lbs Hydraulic Lag 0.01 sec
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Simulation Results
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Simulation Results
Vehicle Weight 2900 lbs Hydraulic Lag 0.007
sec
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Presentation
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Testing - ABS
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Presentation
Wt 2900 lbs
Is this relationship linear or nonlinear?
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Presentation
Wt 2900 lbs
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Results

• Performance Criteria Satisfied.
• Total Time to Stop
• Required ? 15 increase over compact car.
• Actual 12.8 increase.
• Wheel Skid Lock Time
• Required ? 10 increase over compact car.
• Actual 0 increase over compact car.
• Time to market 1.5 months for S/W revisions.
• Cost Less than a 2 increase.