Team 7
Engineering Design 100
Section 024
Prof. Bilen
Colin Kaye, Alberto Vargas, Mike Karpowicz,
Alex DeCoste
Table of Contents

Abstract

Mission Statement

Customer Needs

External Research

Concept Generation

Concept Screening

Concept Selection

Conclusion

References
Abstract

We want to compare the differences between steel and aluminum in order to
create a newly redesigned bus that is safe, environmentally friendly, and is a
cost effective vehicle.
Mission Statement

We chose to redesign the CATA Bus at State College to improve environmental
sustainability and also the efficiency of the transportation system. By utilizing
aluminum to redesign the buses, we are able to create a more efficient bus
that will succeed in the long run compared to steel buses.
Customer Needs

For customer needs, our group polled the people who ride the buses. We
studied the riders who take the colored loops around the campus as well as
riders that live farther away. The riders who take the bus as commuters are
obligated to pay a fare to ride, so their input was much more significant than
the others.

The basic question we asked was what the rider liked about the bus, disliked,
and what should be improved.
Customer Needs
Recorded Need
Interpreted Need

The buses are too crowded

The buses aren’t environmentally friendly • Need green buses

There aren’t enough buses per route
• Need more buses per route

The buses aren’t on time
• Need more timely buses

The bus doesn’t stop long enough
• Need longer stops

Buses are too small
• Need bigger buses

The bus fare is too expensive
• Need cheaper buses

The bus stop information is bad
• Need accurate bus stop information

The buses are too slow

The buses aren’t comfortable

The bus drivers are unfriendly

The bus isn’t safe
• Need less crowded buses
• Need quicker buses
• Need comfortable seats
• Need friendly bus drivers
• Need safe buses
Customer Needs
Customer needs
Need less crowded
buses
Need more buses per
route
Need green buses
Need bigger buses
Need cheaper buses
Need longer stops
Need accurate bus stop
information
Need quicker buses
Need comfortable
seats
Need friendly bus
drivers
Weight
4
Overall importance
2
5
1
4
3
4
3
2
4
7
5
8
9
3
2
6
10
1
11
Need safe buses
4
3
Customer Needs

The weight of each need was based on how frequently the customers
referenced a particular need.

Based on the overall importance, we will focus on the 4 needs:

The environmental impact of building and operating a bus

The safety of the buses

The cost to build a bus*

The cost to operate a bus*
*We assumed that adding more buses and having less crowded buses were dependent
on the cost of buses. CATA can only afford to produce a certain number of buses due
to limited funds.
External Research

What materials are used to make buses today?

Why use steel? … Why use aluminum?

What are the costs to implement each metal in a bus design?

What are the costs to operate a bus out of aluminum/steel?

What is the environmental repercussions of steel/aluminum?
External Research

Attributes of Steel:

Sturdy Material – steel is an extremely strong material used in cars, buildings, and many
other things. It is invaluable in todays world.

Somewhat recyclable – Steel is made of iron ore than can be reused. Two out of three
pounds of steel today is made from old steel. Steel is prone to corrosion however.

Moderately heavy metal – It has great strength for how much it weighs.

Relatively cheap to produce in large quantities.

Stainless Steel is primarily used in automobiles.
External Research

Attributes of Aluminum

Somewhat sturdy – can withstand a fair amount of weight and pressure

Extremely recyclable – aluminum cans that are used for soda and be melted down
and then used to build airplanes. The power of recycling aluminum is great. Also
corrosion resistant.

Very light metal – can help reduce the weight of automobiles but sacrifices
integrity of the hull to do so.

Expensive to produce due to strenuous process of extracting it from ore.

The most widely utilized extricable aluminum alloy is 6063.
External Research - Comparisons

By comparison…

Steel definitely provides a safer bus than aluminum. In a crash, steel could take more of
an impact before yielding than aluminum.

Aluminum is more environmentally friendlier than steel, as it is much more recyclable
and lasts longer than steel in terms of corrosion.

Aluminum is lighter than steel, which means the more aluminum a bus has the lighter
and more fuel efficient it is. Using aluminum instead of steel can improve fuel efficient
from 7-20%.

Steel is cheaper to produce in large quantities compared to aluminum, so implementing
a large amount of aluminum in bus would be very costly. Aluminum is .40$/lb. more
expensive than steel today.
Concept Generation
100% Aluminum
Bus
50% Aluminum/ 50% Steel
100% Steel
We want to find the correct balance between steel and
aluminum to satisfy the customer needs to the best of
our abilities.
Concept Generation
Aluminum Chassis
Aluminum Shell
Bus Shell
Chassis
Steel Chassis
Steel Shell
Aluminum Frame
Bus Frame
Steel Frame
Concept Generation

The concept generation maps that were created helped in the creation of the
CATA bus redesigns by focusing on which parts of the bus can be replaced with
aluminum to help make a highly sustainable and more efficient bus. After
creating a model of the bus in SolidWorks, sustainability tests were run to see
which models were the most sustainable to the environment. As a baseline,
the bus was made with cast stainless steel and the data was taken in terms of
energy consumption and pollution in the environment. For each of the
redesigns, aluminum alloy 6063 was incorporated and then new
measurements were taken.

The first redesign was a bus made completely out of aluminum.

The second redesign is a bus made all from steel, but with the frame made
from aluminum.

The third redesign is a steel bus with an aluminum chassis.

The fourth redesign is an aluminum bus with the frame made out of steel.

The final redesign is an aluminum bus with a chassis made of steel.
Concept Screening

For the bus, we want to implement the correct amounts of aluminum and steel.

There are many parts that go into the bus design the bus.

We focused on the three main parts…
Concept Screening – Bus Components
Bus Frame
Concept Screening – Bus Components
Bus Chassis
Concept Screening – Bus Components
Bus Shell
Concept Generation - Baseline
Model Name:
Steel Bus
Weight:
8.85E+5 kg
Built to last:
10 year
Duration of
use:
10 year
Carbon Footprint
8.4E+7 kg CO2e
Total Energy Consumed 8.6E+8 MJ
Air Acidification
Water Eutrophication
2.4E+5 kg SO2e
2.1E+5 kg PO4e
Material Financial
Impact
66090.20 USD
Concept Screening
Model
Environmental
impact
Safety
Cost to
build
Cost to
operate
Total
Continue
All Steel
-
+
+
-
0
No(baseline)
All Alum.
+
-
-
+
0
No
Steel w/
Alum.
Frame
+
0
+
0
2
Combine
Steel w/
Alum
Chassis
+
+
0
0
2
Combine
Alum. w/ +
Steel
Frame
0
-
+
1
Yes
Alum w/
Steel
Chassis
0
-
+
1
Yes
+
Concept Selection
Model
Environmental
impact
Safety
Cost to build
Cost to operate
Total
Continue?
Criteria
Rank Weighted
(20%)
Rank
Weighted
(20%)
Rank
Weighted Rank
(30%)
Weighted
(30%)
R
All Steel
(baseline)
1
.2
5
1
5
1.5
2
.6
13 3.3 No
Steel w/
Alum
chassis and
frame
4
.8
4
.8
3
.9
4
1.2
15 3.7 Develop!
Alum w/
steel frame
5
1
1
.2
1
.3
5
1.5
12 3.0 No
Alum w/
5
steel chassis
1
2
.4
1
.3
5
1.5
13 3.2 No
W
Conclusions

Steel Bus shell with an aluminum frame and chassis offers the best all-around
qualities.

The most difficult aspect to change is the cost to build the bus, which increases
as more aluminum goes into the bus. Aluminum is naturally more expensive per
pound compared to steel.

The cost to operate however, provides a way to save money on fuel compared to
an all steel bus. The bus is a long term investment, and overtime money will be
saved.

Environmentally, the impact of building and operating the bus is less than
baseline. It also will last more years than the baseline as aluminum doesn’t
corrode as easily, and a large portion of the bus is recyclable!

As for safety, there is still a good deal of steel within the shell of the bus,
protecting it in a crash.
Conclusions

With more money being saved in the long run with these buses, CATA could….

Add more buses to the routes

Reduce the fare

Make bigger buses
All of which satisfy the customer!
References
1. “Center Area Transportation Association Budget” Catabus.com, Nov. 11, 2013
<http://www.catabus.com/AboutCATA/Budget/Budgets/FY20132014FinalBud
get.pdf>
2. “Let’s Go Design – Steel Vs. Aluminum” The Solidworks Blog, November 18th,
2013 <http://blogs.solidworks.com/solidworksblog/2010/08/lets-go-designsteel-vs-aluminum.html>
3. Hatch, John. Aluminum: Properties and Physical Metallurgy.ASM International.
1984.
4. “Aluminum Tests Its Mettle Against Steel in Drive for Lighter Cars”
The Wall Street Journal. Nov. 18, 2013.
<http://online.wsj.com/news/articles/SB100014240527487037269045761926
33836369392>