TO: XLIX Design Firm
FROM: Team 3; Brad Oden, Benjamin Trull, Tyler Lindsey, Jonathan Petrinitz
DATE: 11/6/12
RE: Cover Memo
CC: M. Harkins, P. Franklin
As requested, a technical report, detailing all the work that has been done, has been completed
and the Beam Project’s successfulness has been assessed. Different teams were to build a
beam that met specific requirements while also completing a design package and an excel
calculator.
The design packages, both individual and team, were used as blueprints to the beam. Different
designs were put in the design packages as alternatives to the one design that would eventually
be chosen as the final beam design. Research was also conducted to give a better
understanding of what to put into the design. The excel calculator was built to make quick
calculations for each separate beam design.
After comparing each of the individual beams an I-Beam was chosen to be the final beam
design of the Team Design Package. The beam was constructed in two days using only
basswood, wood glue, ruler, and clamps. The beam was then tested for the deflection at 400
pounds force on the x-axis and 300 pounds force on the y-axis. The beam was within the
specified deflection requirements on both axies.
The beam was completed successfully, though it could have been more successful. The
deflection ratio was not met. Very little importance was placed on the deflection ratio when
designing the beam, meeting the main requirements was the primary objective. Besides the
deflection ratio, the beam was very successful.
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Beam Project Technical
Report
I have neither given nor received any unauthorized help on this assignment, nor witnessed any
violation of the UNC Charlotte Code of Academic Integrity.
Date:
Jonathan Petrinitz
Brad Oden
Hayden Trull
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Tyler Lindsey
Table of Contents
Table of Contents
Summary
Introduction
Problem Statement
Design & Performance Requirements & Constraints
Assumptions
Background Information
Research & Theory
Governing Equations
Methods & Procedures
Figure 1: Beam Excel Calculator
Table 1: Decision Matrix
Figure 2: Beam Being Tested
Observations & Results
Table 2: Observations and Measurements
Discussion
Conclusion & Recommendations
References
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Summary
To begin the project, every team member was required to complete their own design
package with three separate designs. Along with the designs, each member was required to
research prototyping, beam theory, factor of safety, beam loads, etc. The three designs were
limited to I-Beams, H-Beams, and Hollow-Box Beams. The members chose the best of their
three designs and presented them to the rest of the team. The reason for the individual design
package was so that each member of the team could learn the design process and do research
on his own.
After the individual design package was completed, the team met to present each
member’s design. The individual design packages were important because they required each
member to formulate three beams on his own. This way the team had a large pool of twelve
beams to choose the best from. Each member submitted their best design. First the team
checked each member’s beams to ensure they met the design constraints. Then we compared
the beam’s projected performance using a decision matrix. The decision matrix was used
because it takes into account all of the factors that could influence a choice, how those factors
should be weighted, and allows the team to make a decision quantitatively rather than
qualitatively. The team collaborated and wrote a single team design package incorporating
each members best beam design, individual research, calculations, and our decision matrix.
Once the team had decided on the best beam, the calculations were checked by our
professor to ensure their correctness. After the calculations proved to be correct the materials
were requisitioned and construction began. The wood was marked to specific dimensions and
the gluing process began. When the glue holding the joints together was finished drying the
beam was tested to the specified weights. The beam succeeded. In the future it is
recommended to allow at least 24 hours for a glue joint to dry. It is also recommended to
double check your calculations as errors are easy to make and can be catastrophic.
Introduction
Problem Statement
We were tasked with designing a beam made of basswood using mathematical
equations in order to meet the specified requirements in regards to supporting loads, weight
restriction, deflection restrictions, and cost limits. The beam is required to support 400 pounds
on the X-Axis and 300 pounds on the Y-Axis. When loaded on the X-Axis it must deflect at least
0.05 inches and it may not deflect more than 0.20 inches. When loaded on the Y-Axis the beam
must deflect at least 0.03 inches and no more than 0.25 inches. It cannot weigh more than 260
grams. The total cost of wood may not exceed $11.50.
Design & Performance Requirements & Constraints
The beam is required to withstand 400 pounds on the X-Axis and 300 pounds on the Y-axis.
The beam cannot deflect more than .20 of an inch or less than .05 of an inch on the X-axis,
while deflection has to be within .03 to .25 inches for the Y-axis. It can cost no more than
$11.50 and must weigh less than 260 grams, only tools within the discovery box and wood from
the lumber yard can be used to construct the beam.
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Assumptions
The assumption was made that if the calculated deflection of the wood was within the
required limits that it would not break under load. It was also assumed that the wood would be
ideal and free from weakening imperfections. It was also assumed that a safety factor of two
would be sufficient.
Background Information
Research & Theory
Prototypes in Designs: At some point almost every product that we see for sale has at sometime
been a prototype. A prototype can also be called the “first draft” of the final product. The
prototype is like all first drafts and is used as a stepping stone to eventually get to the final,
design. This “first draft” is a functional design but not the final ("What is a Prototype" 2012). The
prototype is tested thoroughly to check for design flaws. Sometimes flaws are found and
changes are made and incorporated into the final product. Companies who mass produce a
product sometimes use “beta testers” ("What is a Prototype" 2012). These testers are used
when a company has a prototype and wants to if see people like it and and how it works under
heavy workload.There may be beta tests that are tested before a product is ready to hit is
released to the public ("ScienceBuddies.org" 2012). The beta testers provide the company with
feedback. This is used to fix any problems and to better the product. In some cases beta testing
is not available to everyone; this is called “closed beta testing.” Testing that is open to the public
is called “open beta” and anyone who is willing to test the product can. By using prototypes in
the design of products, companies can see the changes that need to be made early in
development. Sometimes however this can be a slow process ("What is a Prototype" 2012).
With time, testing, and diligence prototypes begin to mold into the final design.
Physical Prototyping Alternative: Visual prototyping is one alternative to physical prototyping .
Visual prototyping is software based which involves computer modeling systems. This system
can “visualize the prototype’s behavior under real world operating conditions” ("What is Virtual
Prototyping" 2012). This method allows a company to see how the product holds up without
actually creating a tangible product unlike physical prototyping. This testing is done through
various computer programs ("What is Virtual Prototyping" 2012). These computer programs run
mathematical simulations that hold theoretical or computerized loads. Human error and
construction mistakes cannot be assessed ("LairdTech.com" 2012).
Safety Factors in Design: Safety factors, or factors of safety, are used in designs to ensure that
a structures performance is not affected by uncontrollable factors. “This allows for uncertainty in
the design process (Rachel 2012).” Material strength and quality of material (ex. knots in wood)
are some of these uncertainties. Safety factors are used to ensure that the structures are safe
under stress “for yield strength and ultimate strength and are selected depending on how the
forces are applied to a structural component (Philip J. 2009).” Saftey factors are represented
by numbers. This value depends on the materials that are used and the purpose of the structure
as a whole (Rachel 2012). For instance, if something is designed to support a load of 100 pound
force and its safety factor is 3, the strength of the component is 300 pound force (Rachel 2012).
Different Beam Loads: Beams are designed based on the type of load it will support. Beams
are mostly horizontal members and the load is most often acted vertically on the beam or on the
Y-axis ("Members Subjected to Flexural Loads”). Two main loads exist, concentrated and
distributed. A concentrated load acts on the beam in one point or location making them the
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simplest because pressured is only applied to a specific point on the beam. (“Geometry Center”
1996) These are the loads easiest to calculate. A distributed load acts on the beam in more
of a spread out manner. This type of load takes up most of the length of the beam ("Members
Subjected to Flexural Loads”).
Other Uses of Beam Theory: Beams are thought to be used mostly in the construction of
structures. These may include bridges, buildings, etc. Beams are used in these and are also
used in our everyday lives. This research will focus on beams that are used in automobiles.
Vehicle Construction incorporates many beams but the most important is called the “crumple
zone” ("Physics in the Crumple Zone " 2012). Crumple zones in vehicles are usually located in
the front and sometimes in the rear of vehicles ("Physics in the Crumple Zone " 2012). The front
crumple zone is considered the most important due to the fact that head on collisions cause the
most deaths. This sudden stop makes the crash fatal (Meldon 2012). Crumple zones
incorporate plastic beams that “crumple” or fold under forces of certain specific values. This
folding absorbs most of the impact, leading to less impact on the passengers of the car
("Physics in the Crumple Zone " 2012).
Engineering Reports: Engineering reports are the main way to document and communicate in
the workplace. It is a summarization of everything that a team or individual has encountered
and all of the steps that were taken to finish a project. It also communicates and explains all of
the data collected ("Purdue Online Writing Lab" 2012).
Governing Equations
𝑏ℎ3
𝐼=
12
𝑃𝐿3
∆=
48𝐸𝐼
𝑚
𝜌=
𝑣
𝑉 = 𝑙𝑤ℎ
Methods & Procedures
The methodology for for choosing what beam was being used first write an excel beam
calculator that would find designs that meet the requirements with relative ease. The calculator
was built by plugging in the specific values into a design parameter and then plugging formulas
to find if the requirements were met or not. This was essential to quickly finding materials that
work.
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Figure 1: Beam Excel Calculator
Figure 1: Photo Taken by Hayden Trull
With finding the correct materials that would allow the beam to be built within the design
requirements. The design package was made using the designs from the beam calculator, as
well as research. Of the three designs, one was chosen for each team member and brought to
the team to put into the team design package. The team design package was the final step
before the beam to be built was chosen. A decision matrix using the selected beam design
from each team member was used to decide on which beam would be chosen.
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Table 1: Decision Matrix
Table 1 : Image of the decision matrix used in the team design matrix. Photo taken by
Hayden Trull.
The beam selected was an I-Beam designed Hayden Trull. The I-Beam was selected
because more force was being put on the x-axis than the y-axis. The I part of the beam can
hold more than the H part of the beam. It was the most logical choice. The flanges were .25” x
1.75” and the webbing was 0.3125” x 1.375” and weighed 230 grams. It was constructed by
gluing the webbing in the center of one of the flanges, clamping the webbing to the flange, and
letting glue try for a day. After the glue had dried the process was repeated again until testing
time.
The beam was brought in for testing, where a load was put on both the x and the y axis.
400 pounds of force were to be put on the x-axis and 300 pounds of force were to be put on the
y-axis. The deflections were recorded and passed the deflection requirements.
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Figure 2: Beam Being Tested
Figure 2: Photo Taken By Brad Oden
Observations & Results
Table 2: Observations and Measurements
Given
Theoretical
Actual
% Difference
Min 0.05” Max
0.0848”
0.121”
42.69%
0.20”
Deflection Y
Min 0.03” Max
0.1558”
0.169”
8.47%
0.25”
Weight
260g
230g
230g
0%
Table 2: Table showing the calculated deflection, actual deflection, and the percent
difference.
Deflection X
Discussion
The beam was successful in holding the load, and well within the limits for deflection.
The theoretical weight of the beam was calculated at 230 grams which was the exact weight of
the finished beam. This resulted in a 0% margin of error in terms of weight calculation; however,
we left a 30 gram margin of error just in case. Our theoretical Y axis deflection was also very
close to the actual at 8.47% error. This error can be considered to be caused by uncontrollable
factors such as the moisture or integrity of the wood. On the other hand the difference between
theoretical X axis deflection and actual X axis deflection at 42.69% which was far greater than
we had planned, however, we were still within acceptable limits. After recalculating our beam’s
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deflection we ended up with similar deflection values. Therefore, the extraneous deflection of
the beam was caused by uncontrollable factors.
Conclusion & Recommendations
Within finishing the beam deflection test, much reflection has been spent assessing the
entire project. Planning was the first step in the process, as members worked to find three
designs that meet the requirements specified. With the designs, individuals made their own
design package. The designs, research, design calculations, and design drawings were put on
the package with one design from each member to move onto the team design package.
A beam calculator was created to give interns an understanding as to how to use Excel
in the workplace. As well as making the calculator, a team design package was made drawing
information from the individual design packages. A final design was finally picked using a
decision matrix.
Construction of the beam came next. The middle of one flange was measured out
exactly and the webbing was glued to the middle. The joint was clamped and left to dry for two
days before gluing continued. The same process was applied to the other flange and the beam
was left to dry until the day of the test.
When being tested, the beam deflected 0.121” on the x-axis compared to the theoretical
0.0848” calculated before testing, making it a 42.69% difference. The difference was much less
on the Y-axis with a 8.47% difference with a calculated deflection at 0.1558” and the actual
being at 0.169”. Our beam met all of the design requirements except for ratio, which was
calculated roughly to be 1.03. Unfortunately, a 2.00 ratio or better was required to receive the
whole 100 points.
In conclusion, our team worked in a timely manner and communicated on a regular basis
to facilitate an effective work environment. Every member provided one beam that theoretically
fit the design requirements and everyone was able to definitively decide on a single beam. A
lesson learned was the importance of prototyping. Without it, there is a high chance a product
would never work because there are many factors that are not put into calculations. Prototyping
allows the product to become stronger due to learning what it’s weaknesses are. As previously
stated, assembly went smoothly and was completed well before the testing date. In short, our
team followed the guidelines set forth by the project plan to smoothly and effectively complete
the project in a timely manner.
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References
Automotive Plastics. "Physics in the Crumple Zone ." Last modified 2012. Accessed October 23,
2012. http://www.plastics-car.com/CrumpleZone.
onlineschools.org. "What is a Prototype." Last modified 2012. Accessed October 23, 2012.
http://www.onlineschools.org/library/what-is-a-prototype/.
Lecture 21, "Members Subjected to Flexural Loads." Accessed October 23, 2012.
http://nptel.iitm.ac.in/courses/Webcourse-contents/IIT-ROORKEE/strength of
materials/lects & picts/image/lect21/lecture21.htm.
Meldon, Jeffrey. Jeffrey Meldon Associates, "Head On Collisions are one of the Most
Dangerous Types of Crashes." Last modified 2012. Accessed October 23, 2012.
http://www.meldonlaw.com/library/head-on-collisions-causes-dangers.cfm.
Rachel, Burkot. Wise Geek, "What is Factor of Safety?." Last modified 2012. Accessed October
23, 2012. http://www.wisegeek.com/what-is-factor-of-safety.htm.
TWI, "What is Virtual Prototyping." Last modified 2012. Accessed October 23, 2012.
http://www.twi.co.uk/technical-knowledge/faqs/process-faqs/faq-what-is-virtualprototyping/.
The Geometry Center. "The Geometry Center." Last modified 1996. Accessed October 21,
2012. http://www.geom.uiuc.edu/education/calc-init/static-beam/load_simple.html.
Laird Technologies. "LairdTech.com." Last modified 2012. Accessed October 21, 2012.
http://www.lairdtech.com/About-Laird-Technologies/Case-Studies/Optimization-ofThermal-EMI-Solution-Reduces-Design-Time/3/
Philip J., O'Keef. "Engineering Witness Blog." Last modified 2009. Accessed October 21, 2012.
http://www.engineeringexpert.net/Engineering-Expert-Witness-Blog/?tag=factor-ofsafety.
Science Buddies. "ScienceBuddies.org." Last modified 2012. Accessed October 21, 2012.
http://www.sciencebuddies.org/engineering-design-process/engineering-designprototypes.shtml.
Owl. "Purdue Online Writing Lab." Last modified 2012. Accessed October 21, 2012.
http://owl.english.purdue.edu/owl/resource/647/01/.
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Appendix
An Appendix section for all supporting documentation such as detailed drawings, preliminary
sketches, lengthy calculations, computer programs, large data sets, etc.
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