Alan Salas, Kevin Dahms, Jess Zarker, Jose Ordonez, Robbie Moss ENGS 171 Industrial Ecology Redesigning the Bicycle

Recap from last time

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 strength Minimizing CO 2 Minimize CO 2 ρ/ E 1/2 for stiffness Minimize CO 2 ρ/ σ y for strength

Indices for other components PartConfigurationFunction(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 38 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.

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 34% reduction

CO 2 of Entire process 40% reduction

Specifically looking at components 75% reduction 87%

CO 2 of materials 74% reduction 87%

Water-audit of redesigned bike Why isn’t there a significant change???

Economic Analysis Materials: Low alloy steel USD/kg At 3.68 kg, price is $3.35 Bamboo 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”.

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 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” Conclusions and Recommendations

Moving forward… Hemp Wood and ideally… DIAMOND!

Questions?