ENGS 171 Industrial Ecology Redesigning the Bicycle

measlyincompetentUrban and Civil

Nov 29, 2013 (3 years and 10 months ago)

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Alan Salas, Kevin
Dahms
, Jess
Zarker
, Jose Ordonez, Robbie Moss

ENGS 171

Industrial Ecology

Redesigning the Bicycle

Recap from last time

0.00
5000.00
10000.00
15000.00
20000.00
25000.00
Materials
Manufacture
Transport
Use
Disposal/End of Life
Water Use (kg)

Phase

Water Use Audit

0
2
4
6
8
10
12
14
16
18
20
Frame
Wheels
Air
Tube
Fork
Handle
Bar
Crank
Rear
Wheel
Frame
Front
Wheel
Frame
% of Total CO2

Materials: Components with Highest Embodied CO2

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 CO
2
)



Minimizing Embodied Energy



Minimize
H
m
ρ
/ E
1/2


for stiffness



Minimize

H
m
ρ
/
σ
y

for strengt
h




Minimizing CO
2



Minimize

CO
2
ρ/ E
1/
2

for stiffness



Minimize
CO
2
ρ/
σ
y

for strength

Indices for other components

Part

Configuration

Function(s)

Constraint(s)

Objective(s)

Fork

1 Beam (loaded in
bending)

2 Columns (in
compression)

Provide support; link
between handlebar
and front wheel

High stiffness, high
strength

Minimize: mass,
embodied energy,
carbon emissions

Frame

6 Beams (loaded in
bending)

1 Column (in
compression)

Provide structural
support for bike

Handlebar

1 Beam (loaded in
bending)

1 Column (in
compression)

Give direction,
provide stability,
support part of
rider's weight,
platform for break
handles

Seat Mast
Tube

1 Column (in
compression)

Support rider's
weight

Indices for other components

Material Selection

Analysis for seat mast tube
(modeled as a column)

Material Selection

Bamboo!

Low
-
alloy steel

Lower


embodied



energy!

Material Selection

Bamboo!

Low
-
alloy steel

Lower


CO
2

Material Selection

Bamboo!

Lower


density

Low
-
alloy steel

Trade
-
off Strategies

Mass vs. Cost

Bamboo, Softwood and Hardwood

Low
-
alloy
steel

Cheaper

Mass vs. Embodied Energy

Bamboo, Softwood and Hardwood

Low
-
alloy
steel

Less embodied energy

Cost vs. CO
2

Bamboo, Softwood and Hardwood

Low
-
alloy steel

Less CO
2

Cost vs. Embodied Energy

Bamboo, Softwood and Hardwood

Low
-
alloy steel

Less embodied energy

Shape

29 mm

3
8

mm

4.5 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
/i nstructi ons/
bamboobikeki t
/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

-300
-200
-100
0
100
200
300
400
500
?Material
?Manufacture
Transport
?Use
?Disposal
?End of Life
potenti al
Energy
(MJ)

Original
New Design
2nd Life (Remanufactured)
34% reduction

-15
-10
-5
0
5
10
15
20
25
?Material
?Manufacture
Transport
?Use
?Disposal
?End of Life
potenti al
CO2 (kg)

Original
New Design
2nd Life (Remanufactured)
CO
2

of Entire process

40% reduction

Specifically looking at components

0
10
20
30
40
50
60
70
?Frame
Handlebars
?Fork
Seat Tube
Energy ( MJ )

Original
New Design
75% reduction

87%

CO
2

of materials

0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
?Frame
Handlebars
?Fork
Seat Tube
CO2 ( kg )

Original
New Design
74% reduction

87%

Water
-
audit of redesigned bike

0
5000
10000
15000
20000
25000
Materials
Manufacture
Transport
Use
End of Life
kg of Water

Water Audit: Existing vs. Redesign

Original
Redesign
Why isn’t there a significant change???

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:


http://
edition.cnn.com
/2012/05/31/business/bamboo
-
bicycles
-
zambia
-
zambikes
/
index.html?hpt
=hp_c4

“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”.


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:


G
reenhouse
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

Considerations


Industrial infrastructure is currently nonexistent


This is the foundation for a sustainable lifestyle



Saving 91 MJ per bike means saving energy of

245

bananas per unit!!!

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

Conclusions and Recommendations

Moving forward…

Hemp

Wood

Wood

a
nd ideally…

DIAMOND!

Questions?