Team X 1
Index Card Project
Team X:
Sarah Brothers, Margretta Karousis, Mike Kovach,
Dominic Rosace, William Urban
Team X 2
Introduction
Purpose
The purpose of this report is to document the design process and testing of an index card
structure conducted by Team X.
Problem
The assignment was to build a structure that held an optimum amount of weight in comparison to
cost.
The materials and costs consisted of
·3x5 inch Index Cards=$1.00 each
·Folds=$0.50 each
·Staples=$0.75 each
Cost could be calculated by the equation:
Where: ·c=total cost
·i=quantity of index cards
·f=quantity of folds
·s=quantity of staples
Scope
The requirements imposed on this project were:
·the structure had to be at least 1½ inches tall
·all components had to be in contact with each other
·index cards had to be placed on an edge
·all folds had to be a full crease, no curves
·the structure had to hold at least 2 bricks
·index cards could not be torn or cut
Background
Initial research indicated to Team X that triangles are one of the strongest geometric figures and
that columns efficiently carry a heavy load to a foundation. Based on Euler’s formula for a
pinned column, it was noted by the group that maximum weight would be supported by a column
with the shortest unsupported length. The smaller the sides of the column are the closer it
resembles a cylindrical column, which would be the strongest. Center of gravity also plays a part
in the stability of a structure. The lower the center of gravity, the more stable the design will be.
Therefore, the project should be the minimum allowed height. Finally, to ensure the maximum
load, the columns should have the weight evenly distributed. This will help prevent premature
failure of a single column which would lead to a total failure of the structure.
Test and Evaluation
Apparatus
The primary basis of the structure consisted of 4 triangular pillars. These components were
made by folding an index card hot dog style, then proceeding to fold it hamburger style twice,
the remaining was then folded into thirds to create a triangular pillar. These pillars were
connected by an X shape, created by stapling two index cards folded hot dog style at a fold in the
Team X 3
center of each. (Figure 1 & 2) This device consisted of 6 index cards, 5 staples, and 24 folds; the
final cost was $21.75.
Procedure
Team X met four times to develop their index card structure: September 11th, 12th, 18th, and 19th,
2007. The first meeting was spent brainstorming ideas on paper. During the second meeting
they tested several structures, focusing primarily on small shapes. Among the shapes tested were
triangles, hexagons, diamonds, and rectangles. The triangle proved to be the most efficient and
versatile. They discovered a feasible design during their third meeting, and they perfected this
structure during their final meeting. They performed many tests of each idea, most buckled due
to imbalance. They tested their structures by placing a square board over the apparatus and
stacking bricks on the board in layers of eight. (Figure 3 & 4) The structure held 28 bricks
before it finally collapsed due to imbalance. (Figure 5)
Findings
In developing their structure Group X tested small components of structures rather than large
designs, they did this because they found the summation of several weak components to be
equally as weak as the individual parts. They also found the more balanced a structure is the less
likely it is to fail; for this reason they placed the strongest parts of their structure, the pillars, on
the outermost edges.
Conclusion
Assessment
Group X completed the index card project by creating a structure that cost $21.75 and reached
129% efficiency. They believe their structure to be more than a success. This opinion is based
on the equation:
Where:
P=Total Competition Points
b=number of bricks supported
c=cost of structure
According to this equation Group X earned 129 competition points and thus achieved 129%
efficiency.
Recommendation
Group X recommends additional modification to their design to further improve performance.
This can be achieved by developing larger columns in a similar format, and placing these
columns further apart.
References
“Columns: Inelastic Buckling.” Efunda. 20 September 2007 < http://www.efunda.com/
formulae/solid_mechanics/columns/inelastic.cfm>.
Dieter, George. Engineering Design. New York: McGraw-Hill Inc., 1991.
Team X 4
“Ideal Pinned Column Buckling Equation and Calculation, Euler’s Formula.” Engineers
Edge. 20 September 2007 <http://www.engineersedge.com/column_buckling/
column_ideal.htm>.
Team X 5
Appendix
Figure 2: The Structure
Figure 3: Strategic Stacking
Figure 4: The Stack
Team X 6
Figure 5: Failure!!