1/18/09 - l7 teamworikcopyright 2009 - joanne degroat, ece, osu1 first design

1/18/09 - L7 Teamworik Copyright 2009 - Joanne DeGroat, ECE, OSU 1

First Design

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My First Design Engineers Design When did you first design something? General Guidelines

First Designs In school students encounter situations for

design Science Fairs in highschool Physics and chemistry classes

If not in high school then in college In many programs of study there are class that are

oriented this way. (The freshman program here at OSU has a major design build project)

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Undergraduate class Several problems to address in an

undergraduate class that I had. How far can a goose fly? How far can a diesel locomotive travel on 1

ounce of diesel fuel? Within the constraints, design a structure that will

support the highest load-to-weight ratio.

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Strength-to-Weight Ratio Size constriants Material constraint

Balsawood Success criteria

Strength to weight ratio

Other constraint No laminating

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Design of Balsa wood structure Assignment set specifications Attempted and did initial testing on a couple

of structures after purchase of balsawood. Then did analysis Thought occurred to me – what is strongest

structure? Construction – I beams Highest moment of inertial structural members I beams and channel beams.

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The resulting structure

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Used a buttress on the I beam where the angled channel beams meet

The resulting structure

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Final Design Used an I beam in the vertical structure with the

side toward the load a little thicker to avoid crushing.

Top and bottom and angled members were channel beams.

Were allowed up to 4 inches wide but used only 2 inches for total weight.

A 12 oz structure ended up supporting 240 pounds before failure.

Strength to weight ratio = 320

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Another design Wanted a skateboard – couldn’t afford one. Has an old pair of clamp-on skates that were too

small. My cousin and I took them apart so you had the

front wheel truck and the rear wheel truck from each.

We bolted these onto a piece of wood to make two skateboards which we were able to use for several years…… (and several bump and bruises)

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The assignment MY FIRST DESIGN

Choose something that you designed in your lifetime.

Write up the design experience. SECTIONS The motivation – why you did it The specification – what was it supposed to do The initial ideas for the design implementation The final implementation The success/failure of the implementation

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