WENTWORTH
Problem Definition:
Identifying Constraints
Institute of Technology
Chapter 5
Problem Definition:
Identifying Constraints
The more constraints one imposes, the more one frees one’s self. And the
arbitrariness of the constraint serves only to obtain precision of execution.
Igor Stravinsky
Engineering Design
Spring, 2015
MECHANICAL ENGINEERING AND TECHNOLOGY DEPARTMENT
WENTWORTH
Problem Definition:
Identifying Constraints
Institute of Technology
Our 5 stage prescriptive model of the design process. Rectangles are the five stages,
with the output for each stage shown as ovals.
A problem well stated is a problem half-solved.
Engineering Design
Spring, 2015
Charles Kettering
MECHANICAL ENGINEERING AND TECHNOLOGY DEPARTMENT
WENTWORTH
Problem Definition:
Identifying Constraints
Institute of Technology
Stage Two: Conceptual Design
Conceptual Design: Translating Customer Requirements into Engineering Specifications
Objectives Analysis
•
Develop metrics for objectives
•
•
•
•
Constraints Analysis
•
Set limits or boundaries
Functional Analysis
•
Establish functional specifications
•
Establish means for functions
Generate design alternatives
Refine and apply metrics to design alternatives
Establish major attributes
Choose a design concept
Problems are hidden opportunities, and constraints can actually boost creativity.
Martin Villeneuve
Engineering Design
Spring, 2015
MECHANICAL ENGINEERING AND TECHNOLOGY DEPARTMENT
WENTWORTH
Problem Definition:
Identifying Constraints
Institute of Technology
Constraints Analysis
• Set limits or boundaries
5.1 Identifying and Setting the Client’s Limits
I thing frugality drives innovation, just like other constraints do. One of the only
ways to get out of a tight box is to invent your way out.
Jeff Bezos
Engineering Design
Spring, 2015
MECHANICAL ENGINEERING AND TECHNOLOGY DEPARTMENT
WENTWORTH
Problem Definition:
Identifying Constraints
Institute of Technology
Objectives and Constraints are closely
related, but not interchangeable
Constraints:
• Limit the size of the design space
• Enable team to reject unacceptable alternatives
• Typically expressed in terms of quantifiable units: cost, weight, strength
Hell, there are no rules here – we’re trying to accomplish something
Thomas A. Edison
Engineering Design
Spring, 2015
MECHANICAL ENGINEERING AND TECHNOLOGY DEPARTMENT
WENTWORTH
Problem Definition:
Identifying Constraints
Institute of Technology
Chapter 3
A starting list of
safe ladder
attributes:
O = Objectives
C = Constraints
F = Functions
M = Means
Engineering Design
Spring, 2015
MECHANICAL ENGINEERING AND TECHNOLOGY DEPARTMENT
WENTWORTH
Problem Definition:
Identifying Constraints
Institute of Technology
Chapter 4
Objectives Tree
A refinement
of the list
clustering
similar ideas
Engineering Design
Spring, 2015
MECHANICAL ENGINEERING AND TECHNOLOGY DEPARTMENT
WENTWORTH
Problem Definition:
Identifying Constraints
Institute of Technology
TABLE 5.1 The list of safe ladder constraints extracted from
the list of attributes Table 3.1
Engineering Design
O
Objectives
C
Constraints
F
Functions
M
Means
Spring, 2015
MECHANICAL ENGINEERING AND TECHNOLOGY DEPARTMENT
WENTWORTH
Problem Definition:
Identifying Constraints
Institute of Technology
Objectives Tree: Chapter 4
Engineering Design
Spring, 2015
MECHANICAL ENGINEERING AND TECHNOLOGY DEPARTMENT
WENTWORTH
Problem Definition:
Identifying Constraints
Institute of Technology
Objectives Tree with
Constraints added
You can have brilliant ideas, but if you can’t get them across, your
ideas won’t get you anywhere. Lee Iacocca
Engineering Design
Spring, 2015
MECHANICAL ENGINEERING AND TECHNOLOGY DEPARTMENT
WENTWORTH
Problem Definition:
Identifying Constraints
Institute of Technology
Tools in your
laptop
Visio
MS Project
Be passionate about the problem.
Be objective about the solution.
Monique Fuchs
Engineering Design
Spring, 2015
MECHANICAL ENGINEERING AND TECHNOLOGY DEPARTMENT
WENTWORTH
Problem Definition:
Identifying Constraints
Institute of Technology
So, from here:
• Pull out the list of attributes required for your project
• Identify attributes that are, or may be constraints
• Work to refine them as close to engineering specifications as
possible. Rather than simply stating: meet industrial standards, or
OSHA requirements, do some research to identify these.
• If you haven’t already, sketch out your objectives tree, and then
add the constraints. Be sure to somehow visually differentiate
them from the objectives.
• Take a moment to look over Visio and Project software to see if
they can be useful to you here to create a more professional and
practiced looking graphic.
Remember: the college of engineering is standardizing on this 5 stage
design process for all project work done in your remaining years at WIT.
Any effort you put in here can be used in future project work.
Engineering Design
Spring, 2015
MECHANICAL ENGINEERING AND TECHNOLOGY DEPARTMENT