1.2 A basic vocabulary for engineering design

Question 1

What is engineering design?

Answer 1

Engineering design is:

• The systematic, intelligent generation of specifications for artifacts whose form and function achieve stated objectives and satisfy specified constraints.
• A thoughtful process for generating plans or schemes for devices, systems, or processes that attain given objectives while adhering to specified constraints.
• An activity that intends to produce a description of an artifice in terms of its organization and functioning - its interface between inner and outer environments.

Question 2

What is a design objective?

Answer 2

Design objective (n): a feature or behavior that we wish the design to have or exhibit.

Question 3

What is a design constraint?

Answer 3

Design constraint (n): a limit or restriction on the features or behaviors of the design. A proposed design is unacceptable if these limits are violated.

Question 4

Define Artifacts.

Answer 4

Artifacts: human-made objects; artificial, man-made objects, the “things” or devices that are being designed.

Question 5

Define Form.

Answer 5

Form: the shape of the artifact; the shape and structure of something as distinguished from its material.

Question 6

Define Function.

Answer 6

Function: things the artifact (designed device or system) is supposed to do

Question 7

Define Specifications.

Answer 7

Specifications are:

• Descriptions of properties of the object being designed
• Detailed descriptions of the designed device
• A scale on which the achievement of a design’s functions can be measured
• Engineering statements of the extent to which functions are performed by a design.

Question 8

Define Objectives.

Answer 8

Objectives: attributes of the designed artifact that make it “good”

Question 9

Define Constraints.

Answer 9

Constraints: specifications which the artifact must meet to be acceptable

Question 10

Define Means.

Answer 10

Means (n): a way or a method to make a function happen

Question 11

What is a Metric?

Answer 11

Metric (n): a standard of measurement; in the context of engineering design, a scale on which the achievement of a design’s objectives can be measured and assessed.

Question 12

What are three examples of things that specifications may specify?

Answer 12

Specifications may specify:

• Values for particular functions or design features
• Procedures for calculating functions or behaviors of the design
• Performance levels that must be attained by the design

Question 13

Relate designed objects to systems?

Answer 13

Design is an activity that intends to produce a description of an artifice in terms of its organization and functioning - its interface between inner and outer environments.

This definition places designed objects in a systems context that recognizes that any artifact operates as part of a system that includes the world around it. In this sense, all design is systems design because devices, systems, and processes must each operate within and interact with their surrounding environments.

Question 14

What is a key issue in engineering design?

Answer 14

Communication is a key issue in engineering design.

Question 15

Do engineering designers produce their artifacts?

Answer 15

Engineering designers do not typically produce their artifacts, except in the form of prototypes and proofs of concept.

Question 16

What is the ultimate product of most contemporary design?

Answer 16

The ultimate product of most contemporary design is a set of fabrication specifications for others to use in making the artifacts.

Question 17

For what are prototypes useful?

Answer 17

Prototypes are useful for understanding the design space and demonstrating the feasibility of the design.

Question 18

What do fabrication specifications enable?

Answer 18

Fabrication specifications provide a detailed description of the designed device so that it can be assembled or manufactured, thus separating the “designing” from the “making.”

Question 19

Why is it imperative for the “maker” to capture the designer’s intent?

Answer 19

Inability to capture the designer’s intent can lead to catastrophe.

Question 20

Describe an example of a situation in which failure to capture the designer’s intent led to catastrophe.

Answer 20

In 1981, a suspended walkway across the central atrium in the Hyatt Regency Hotel in Kansas City collapsed because a contractor fabricated the connections for the walkways in a manner different than intended by the original designer. 114 people died, and millions of truss dollars of damage was sustained.

Question 21

What led to the problem with the suspended walkway in the Kansas City Hyatt Regency Hotel?

Answer 21

• In the design, walkways at the second and fourth floors were hung from the same set of threaded rods that would carry their weights and loads to a roof truss.
• The fabricator was unable to procure threaded rods sufficiently long (i.e., 24ft.) to suspend the second-floor walkway from the roof truss
• Instead, it was hung from the fourth-floor walkway with shorter rods.
• The supports of the fourth-floor walkway were not designed to carry the second-floor walkway in addition to its own dead and live loads

Question 22

Visually describe the difference between the original design and the constructed artifact of the walkway suspension connection in the Regency Hyatt House in Kansas City.

Answer 22