Composite TweelTM

for a Bicycle

Aer E 423 Project

Katarzyna Szemplinska

12/13/2008

Michelin’s product development◦ Tire and wheel combined into one – TweelTM

TweelTM objectives◦ Replace conventional tires◦ Reduce maintenance costs◦ Improve performance

Background

Apply TweelTM concept to bicycle wheels

Analyze TweelTM feasibility and performance

Project Description

Different spoke designs

Multiple composite materials combinations

Assumptions:◦ Load is split equally between the two wheels◦ Load is applied vertically

Initial configuration:◦ Outer Rim Diameter = 24 in.◦ Inner Rim Diameter = 4 in.◦ Load per Wheel = 90 lbs.

Project Design

Spokes: Carbon fiber prepreg 4-ply layup Cured in an autoclave Warping

Outer and Inner Rim: Fiberglass with Epoxy 4-ply hand layup Cured at room temperature

Spoke Reinforcement: Fiberglass with Epoxy 2-ply hand layup Cured at room temperature

Mold Structure: Styrofoam Hand cut

Manufacturing

Final Product

Compression testing◦ MTS testing machine

Preliminary testing: Spoke

Testing

-0.0

1

-1.5

6125

1128

3791

3E-1

7

0.00

9999

9999

9999

999

0.02

0.03

0.04

0.05

0

40

80

120

4-ply 5-ply

Axial Deflection [in]

Axia

l Lo

ad

[lb

f]

TweelTM Compression Testing

Testing

0.0 0.5 1.0 1.5 2.0 2.5

-4

0

4

8

12

16

20

24

Axial Deflection [in]

Axia

l Lo

ad

[lb

f]

Testing

Spoke bending was successful Rim/spoke interface strength was not

sufficient Outer rim flexibility needs to be eliminated

◦ Load transfer to spokes Concept is feasible Performance evaluation with improved

design

Results

Questions?