Engineering Fundamentals: An Introduction to Engineering, 4th ed.c

Step 7: Optimization

Based on results obtained from Step 6, modifications were made to the design and

additional analyses performed. The finite element numerical experiments helped

reshape the mounting bracket significantly to better withstand loading conditions.

The results of numerical experiments dealing with propeller performance were also

used to optimize the shape of the propeller for the final design. Many hours of

testing also helped with the optimization of the final design. The testing included

actual field testing in water and simulated life testing in labs.

Step 8: Presentation

The product development process took approximately two years. During this

period, the design engineers gave weekly progress reports to the rest of design

group; quarterly status oral and written reports were given to marketing depart-

ment and the group vice president in the headquarters. At the end of the proj-

ect, a final presentation was given to the Board of Directors by the lead

mechanical and electrical design engineers. The presentation addressed several

issues including development cost, unit cost, market outlook, performance char-

acteristics, testing results, and environmental impact. The duration of presenta-

Actual testing of the system in a lake. tions ranged from 15 minutes to an entire afternoon.

Source: Peter M. Kjeer

Testing of the system in a laboratory setting.

Source: Peter M. Kjeer

200.0

Thrust vs. HP for Various Prop Diameters

150.0

100.0

Thrust (lbs)

HP

50.0

0.0

0 0.5 1 1.5 2 2.5 3.53 4 4.5 5

11" Diameter Prop

12" Diameter Prop

13" Diameter Prop

14" Diameter Prop

15" Diameter Prop

The thrust vs. horsepower results for different diameter propellers.

Engineers used ProMechanica®to conduct numerical experiments on the motor.

90 Chapter 3 Introduction to Engineering Design

Source: Case prepared by Peter M. Kjeer

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