ENGS 171
Industrial Ecology
Redesigning the Bicycle
Alan Salas, Kevin Dahms, Jess Zarker, Jose Ordonez, Robbie Moss
Recap from last time
25000.00
Water Use Audit
Water Use (kg)
20000.00
15000.00
10000.00
5000.00
0.00
Materials
Manufacture
Transport
Phase
Use
Disposal/End of Life
% of Total CO2
Materials: Components with Highest Embodied CO2
20
18
16
14
12
10
8
6
4
2
0
Frame Wheels
Air
Tube
Fork
Handle Crank Rear Front
Bar
Wheel Wheel
Frame Frame
Part 2: Redesign
Design Requirements
Seat Mast Tube
FUNCTION:
To support the weight of the person. Acts as a column in
compression
OBJECTIVES:
Ideally, minimize environmental impact and mass
CONSTRAINTS:
Recyclable
High strength and stiffness
FREE VARIABLES:
Material choice, shape, color
Indices
For minimizing environmental impact
(embodied energy and CO2)
Minimizing Embodied Energy
Minimize Hmρ/ E1/2 for stiffness
Minimize Hmρ/ σy for strength
Minimizing CO2
Minimize CO2ρ/ E1/2 for stiffness
Minimize CO2ρ/ σy for strength
Indices for other components
Part
Configuration
Function(s)
Constraint(s)
1 Beam (loaded in
Provide support; link
bending)
Fork
between handlebar
2 Columns (in
and front wheel
compression)
6 Beams (loaded in
bending)
Provide structural
Frame
1 Column (in
support for bike
compression)
High stiffness, high
strength
Give direction,
1 Beam (loaded in
provide stability,
bending)
support part of
Handlebar
1 Column (in
rider's weight,
compression)
platform for break
handles
Seat Mast
1 Column (in
Support rider's
Tube
compression)
weight
Objective(s)
Minimize: mass,
embodied energy,
carbon emissions
Indices for other components
Material Selection
Analysis for seat mast tube
(modeled as a column)
Material Selection
Lower
embodied
energy!
Low-alloy steel
Bamboo!
Material Selection
Low-alloy steel
Lower
CO2
Bamboo!
Material Selection
Lower
density
Bamboo!
Low-alloy steel
Trade-off Strategies
Mass vs. Cost
Cheaper
Lowalloy
steel
Bamboo, Softwood and Hardwood
Mass vs. Embodied Energy
Less embodied energy
Lowalloy
steel
Bamboo, Softwood and Hardwood
Cost vs. CO2
Less CO2
Low-alloy steel
Bamboo, Softwood and Hardwood
Cost vs. Embodied Energy
Less embodied energy
Low-alloy steel
Bamboo, Softwood and Hardwood
Shape
4.5 mm
29 mm
38 mm
Shape
- These specifications are for Iron bamboo, which is the
strongest type
- If it is a more flexible bamboo, use wider and thicker tubing
- If internal diameter is less than 29 mm, there will be a hoop
stress, which we didn’t look into carefully in this analysis.
http://www.useful-arts.com/sua/instructions/bamboobikekit/harvest/
Use Phase Analysis
• Negligible environmental impact
• NEXT Bike
• Maintenance: paint, wheels, lost accessories, oil
• Once child grows, bike becomes obsolete
Use Phase Analysis (cont.)
• BamBIKE:
• Introduce a service program
• Convert the product into a service
• Incentive: offer free repairs (only cost is
purchasing the parts), offer discounts, etc.
• Return old bike, obtain new larger bike at a
discount
“If your child grows
faster than bamboo,
we have a solution
for you!”
Discussion of Redesign
Frame
Joints + bamboo
Fork
Handle bar
Seat tube
Eco-Audit of redesigned bike
500
400
Original
34% reduction
New Design
Energy (MJ)
300
2nd Life (Remanufactured)
200
100
0
Material
-100
-200
-300
Manufacture
Transport
Use
Disposal
End of Life
potential
CO2 of Entire process
25
CO2 (kg)
20
Original
40% reduction
15
New Design
10
2nd Life (Remanufactured)
5
0
Material
-5
-10
-15
Manufacture
Transport
Use
Disposal
End of Life
potential
Specifically looking at components
70
60
Original
75% reduction
Energy ( MJ )
50
New Design
40
30
20
87%
10
0
Frame
Fork
Handlebars
Seat Tube
CO2 of materials
4.5
4
74% reduction
3.5
Original
CO2 ( kg )
3
New Design
2.5
2
1.5
1
87%
0.5
0
Frame
Fork
Handlebars
Seat Tube
Water-audit of redesigned bike
25000
Water Audit: Existing vs. Redesign
20000
Why isn’t there a significant change???
kg of Water
15000
Original
Redesign
10000
5000
0
Materials
Manufacture
Transport
Use
End of Life
Economic Analysis
• Materials:
• Low alloy steel
• 0.89-0.93 USD/kg
• At 3.68 kg, price is $3.35
• Bamboo
• 1.37-2.05 USD/kg
• At 0.4 kg, price is $0.82
• BUT, labor is a problem:
• More labor intensive to assemble BamBIKE, so higher costs are
associated
• This is why it is currently only offered to very specialized, high end
consumers
Economic Analysis
• CNN article published today about a bamboo bike company
located in Zambia:
“Each frame takes between 40 and 60
man hours to make […] Every piece of
bamboo is having different colors,
different bend, so every frame is
unique."
• That explains the high costs, and why these “high-end,
lightweight bicycles” have “a price tag of around $900”
and are “primarily aimed at the international market”.
http://edition.cnn.com/2012/05/31/business/bamboo-bicycles-zambia-zambikes/index.html?hpt=hp_c4
Considering Aesthetics: Paint and Plastics
Aesthetics are a major feature
refractive quality of paint,
extra features (painted plastic),
logo designs
Aesthetics are also subjective; malleable
• Don’t outweigh the environmental impacts:
• Greenhouse gas emissions: VOCs, CO2,
NOx, SOx , and PM
• Health Concerns for workers
• “Eco-Design”
Water-based paint
Water-based non-toxic wood varnish
logo
Conclusions and Recommendations
Findings
• Bamboo is an appropriate substitute for steel
• Saving 91 MJ per bike means saving energy of
245 bananas per unit!!!
Considerations
• Industrial infrastructure is currently nonexistent
• This is the foundation for a sustainable lifestyle
Conclusions and Recommendations
There are other important benefits of bamboo
that could be further exploited:
“One of nature's fastest growing resources”
“Has great shock absorbing abilities that
contribute to a smooth and eco-friendly ride”
http://edition.cnn.com/2012/05/31/business/bamboo-bicycles-zambia-zambikes/index.html?hpt=hp_c4
Moving forward…
Hemp
Wood
Wood
and ideally…
DIAMOND!
Questions?