1. The University of Nebraska - Lincoln
Mechanical and Materials Engineering
MECH 447
Senior Capstone Project
Measurement Device for Hose Failure for
Union Pacific
Prepared for:
Union Pacific
Dr. Jung Yul Lim
Dr. Timothy Wei
By:
Ismail Al Hooti
Hamood Al Rhabi
Adam Elwood
Taylor Kerl
Layne Krahn
3. Executive Summary
__________________________________________________________________________
This report presents the design of a measurement device for hose connection failure for
Union Pacific railroad. Gladhand attachments for brake hoses experience peaking forces that
cause the hoses to come detached during service. The experiment uses accelerometers to
study and analyze the behavior of the system so that Union Pacific can acquire quantitative data
on the peaking force and torque that causes the gladhand assembly to separate. Ultimately, this
data can be used as a relatively low cost solution to analyze different gladhand designs against
each other in order to select the most robust design for adaption and integration into the
locomotive fleet.
The acceleration behavior is directly proportional to the force and torque behavior
through Newton’s second law and torque relationship. Because the gladhand and hoses are
nearly identical on each side, this simplistic approach will yield a direct measurement that can
be used to calculate the key metrics of the system. In this design, three tri-axis accelerometers
are placed on each hose, producing six total data points for full system characterization. An
accelerometer is placed on the approximate center of rotation on the gladhand itself, another on
the crimped clamp that connects the hose to the gladhand, and finally, one accelerometer is
placed on the hose to see how any impulse might propagate through the system. The
accelerometers are attached to the gladhand assembly using 3M Urethane Foam 4318 double
sided tape.
This report details the proof of concept for the peaking force measurement. This data
acquisition system is to be used in Union Pacific’s test laboratory for analysis of different
gladhand designs. The wireless transmission for the accelerometers however would allow for
2
4. eventual integration onto a hose system in service in the field should Union Pacific choose to
pursue such an experiment.
Project Statement
__________________________________________________________________________
Students from the University of Nebraska - Lincoln in partnership with a team from the
Locomotive Engineering and Quality - Mechanical branch at Union Pacific will develop the
design of an air hose attachment that will allow Union Pacific to measure the characteristics,
specifically torque and peak forces, that cause the attachments to come unhinged during
service. This design will be a part of the Mechanical and Materials Department capstone project
for the Mechanical Engineering curriculum.
Overall Goal
__________________________________________________________________________
The goal of this project is to design a test system to examine and analyze the behavior
of a gladhand assembly used as an air brake connection on Union Pacific trains.
Background
__________________________________________________________________________
Union Pacific train cars are equipped with an air pressure actuated brake system. The
system is pressurized by pumps located in the locomotive car. When cars are connected, the air
hoses passing from one car to the next are also linked together, pressurizing each braking
system. The type of connection used on the ends of each hose are known as gladhands.
3
5. Image 1: Brake hose assembly on train connection (Union Pacific, 2016).
Gladhands have a rotational locking design. This is used for quasi automation in hose
attachment and disconnecting during cars. The gladhands are designed such that they can
come together and mate when in the correct orientation. In the nominal service state on the cars
the gladhands are supposed to stay fully locked and connected.
Image 2: Gladhand connection when fully established and fully extension (right), and maximum
angle before peaking (left) (Union Pacific, 2016).
When the train cars are scheduled to separate, the gladhands will come
apart through a peaking operation through which they rotate about each other and separate.
During train operation the glad hands have been known to inadvertently disconnect. The
disconnection of even one link along the entire system will cause the brakes to engage on every
car. This means that the train operators will have to stop to find the faulty connection and
reattach it. This delay can cause shipments to be late, delays for other trains using the same
4
6. trackline, and overall loss of efficiency for the affected trains.
The main issue that Union Pacific is facing is the non-universal designs presented by
different gladhand developers. Different gladhand developers use different gaskets, gladhand
shape, and locking designs. Each company claims that their gladhands are more resistant to
peaking but so far Union Pacific has no way of measuring the peaking forces on new gladhand
designs. They are therefore unable to compare these different designs to select the best
gladhands for their trains.
Approach
__________________________________________________________________________
The team began by drawing a free body diagram of the gladhand system to break down
the forces acting on the system. By analyzing the free body diagram, three key metrics can be
seen acting on each of the glad hands; Axial force (Fx), Transverse force (Fy), and Moment (M)
acting on the center of the glad hand. Since the hoses and the glad hands are uniform on each
side, the mass is constant. The acceleration is then the only variable. When a train decelerates,
the join between two train cars compresses which will applies a large axial force on both side on
the gladhand assembly. Since the hoses are semi-rigid, the axial forces cause the center of the
glad hand assembly to lift up. This will apply vertical forces on the assembly that will cause the
gladhand to rotate and separate.
As a solution, we decided to use accelerometers to detect and characterize the behavior
of the hoses and the gladhands. There are two types of accelerometers: Angular
accelerometers and Linear accelerometers. Each type of accelerometer has its own pros and
cons. 3-axis linear accelerometers can be purchased cheaply and measure acceleration based
on orientation. On the other hand, the angular accelerometer measures the angular rotation of
5
7. the object during operation which makes it easier to measure the moment applied on the center
of the gladhands.
Using the characterizing behavior detected by the accelerometers, Newton’s second law,
and the following torque relationship:
in(θ)τ = F * r * s
where “r” is the distance from the center of rotation and “F” is the force obtained by multiplying
the recorded acceleration by the measured gladhand mass. As a result, this relationship can
help visualize and analyze the torque and force behavior of the hoses and the gladhands.
There are many options that can be considered in terms of efficiency, accuracy, and
cost. We narrowed this to three different setups to propose to Union Pacific. First, two linear
accelerometers used on each side of the assembly for a total of four linear accelerometers. This
layout will enable the accelerometer to characterize the system based on hose behavior and
clamp behavior. The benefit of this option is that the linear accelerometers are less expensive
than the angular accelerometers. However, this option is less precise when analyzing the
angular movement of the gladhands due to the accelerometers not analyzing the center of
rotation behavior. Second, one angular accelerometer used on the gladhand and one linear
accelerometer on the hose for a total of four accelerometers; one angular and one linear on
each side. This option is the more accurate option than option 1 since it uses the angular
accelerometer to characterize the glad hands rotational behavior and a linear accelerometer to
analyze the effect of the hose on the gladhand. However, it’s the most expensive option since it
uses both types of accelerometers and the angular accelerometer is very expensive in
comparison to linear accelerometer. Third, is to use six 3-dimensional linear accelerometers;
three on each gladhand. This setup will characterize the rotational behavior of the gladhands
more accurately and it will study the behavior of the hose on the gladhand too.
6
8. To help analyze the design concepts, a pugh matrix evaluation was performed to
determine which concept should be carried forward into our preliminary design. The analysis is
given in two iterations that are reflected in table 1 and 2 below.
Table 1: First iteration of the Pugh matrix analysis.
Table 2: Second iteration of the Pugh matrix analysis.
From these pugh matrices, concept 3 was chosen for our initial design proposal.
Our team performed Failure Modes and Effects Analysis (FMEA) analysis for the
accelerometer to see how it aligned with axiomatic design principles and also to study the
modes that could result in failure. Table 3 shows this FMEA analysis. “The data is off with bad
results consequence” yielded the highest value of 336 RPN, which is where the failure is
7
9. expected. “The data is off with bad designs consequence” could also cause issues. Union
Pacific can use this data as a reference of issues to be cautious of. Moreover, the table shows
the causes that might lead to failure and the severity of each cause.
Function Failure Failure
Mode
Consequences Severity Causes Occurrence Detection
Method
Detection
Rating
RPN Actions
Recording
acceleration
data
Doesn’t
record
data
Data
points off
Bad Results 6 Bad
connection
8 Check 7 336 Regular
maintenance
Bad designs 6 Bad data 3 Reprogra
m
6 108
Not
recording
data
Test stops 5 Sensor off 3 Swap
out/reatta
ched
2 30
Too far
away from
receiver
2 look 3 30
Turned off Test stops 5 Switched off 5 look 1 25
Table 3: FMEA analysis of the accelerometers on hose experiment.
Key Challenges
__________________________________________________________________________
There were many difficulties faced by the group throughout the design process. In the
beginning, the team faced some misunderstanding of the proposed problem. The objective of
the project was not clear. One part of the proposal included the redesign of the gasket inside the
gladhands, while the force analysis tool was another. While one component plays into the
results of the other, the group went back and forth on which project was going to be tackled.
This caused some delays at the beginning. Eventually the decision was made to move forward
with the force analysis device to be used in the testing rigs to analyze various gladhands. The
8
10. idea is that if UP has a way to quantify peaking forces from different gladhand attachments, they
will be able to derive the best gasket and other component designs from those tests.
From there, choosing between two main ideas took a great deal of time. The first idea
was to use a torque meter to analyze the behavior of the gladhands. The second idea was to
use accelerometers to observe the behavior of the gladhand. The torque meter would provide
the advantage of directly measuring the torque output of the system. However, while
researching various types of torque meters it was discovered that mounting such a device would
be extremely difficult. The team considered a hand crimp type mechanism, but again ran into
mounting and orientation difficulties. The accelerometer would measure accelerations on the
entire system, from which force and torque could be derived using Newton’s second law and the
torque relationship equation. While this approach posed extra steps and further data analysis,
the simplicity and cost comparison to a torque meter attachment was alluring.
Eventually, the accelerometer was selected over the torque meter because it was less
intrusive and less restrictive on the system. After choosing to pursue the accelerometer method,
the team then had to decide which accelerometers to use and how to orient the accelerometers
on the test rig for the most effective data acquisition.
In addition to choosing the type of accelerometers, another challenge was deciding on
how to obtain the data from the accelerometers. This depends on the type of the accelerometer
because some accelerometers have a wireless receiver system that makes it easier for the
tester to gather data.
With the accelerometer method chosen for the approach to the solution, the team set out
to answer some of the key challenges posed with this method to develop a preliminary design to
present to Union Pacific. This design is expected to work sufficiently with a high likeliness of
achieving the goal of determining what causes the gladhands to separate.
9
11. Preliminary Design
__________________________________________________________________________
In order to fully comprehend the problem, Union Pacific gave our team a gladhand
assembly to use to try to further characterize the system. Having this physical model of the
system for the team to mentally deconstruct proved to be very valuable. Originally, the concept
of applying a torque meter to the apparatus was very appealing. Using a clamp to measure the
forces of the two hoses coming together causing rotation would be difficult, but possible.
However, as the team further broke down the problem, potential for a more simple approach
revealed itself.
Figure 3 shows the free body diagram breakdown of the critical system components.
Fx(t) represents the axial forces resulting from the hoses attached to the train cars coming
closer together and farther apart. Because of the nature of the hoses, as they move closer
together there is a resulting physical displacement in the Fy(t), transverse direction. This
displacement results in an offset in the transverse forces creating a moment about the center of
rotation of the gladhands. The team came to the conclusion that it was this offset of forces that
could be causing the gladhands to separate while in service.
10
12. Figure 3: Free Body Diagram of Gladhand Attachment.
When approaching the problem from this level, the solution to analyzing the forces did
not need to be a torque meter, but almost all of the system characteristics could be obtained
from the acceleration of the system. Because the gladhands are essentially identical on both
sides, the mass of the system is constant, and the forces can be obtained using Newton’s
Second Law, F=ma. If the acceleration of the system could be measured, the corresponding
forces are easily derived, and with sensor position information torque is also easily calculated.
In this case, accelerometers could be used for dynamic, real time data for the motion of the
gladhand assembly.
Once the conceptual design was completed, we proposed three accelerometer
configurations to Union Pacific to allow them to choose the ideal setup for their testing rig. After
11
13. discussing the advantages and disadvantages of each setup, the setup shown in Figure 4 was
agreed upon by both parties. This would be the foundation for our physical setup.
Figure 4: First proposed solution. Four 3-axis linear accelerometers
Figure 5: Second proposed solution. One central angular accelerometer.
Figure 6: Third proposed solution. One central angular accelerometer and two 3-axis linear
accelerometers.
12
14. Critical Design
__________________________________________________________________________
Once an accelerometer configuration had been agreed upon, we needed to find
accelerometers that would meet or exceed the requirements of our design. Ideally we would
need a 3-axis linear accelerometer that had a relatively high sampling rate. We chose to use the
Monnit Wireless Accelerometer - G-Force Snapshot because of their size, wireless transmission
capability, and their 3-axis functionality.
Figure 7: Coin cell accelerometer chosen for final design setup
We decided to use six total accelerometers to fully capture all aspects of the behavior of
the gladhand system during a test. One accelerometer would be placed on the midpoint of each
hose and one on each crimp that connects the hose to the gladhand. Two final accelerometers
would be placed on the center of rotation of each the gladhand assembly. Since the center of
rotation will move as one fixed entity until the gladhands fully peak and separate, only one
accelerometer is necessary here. This configuration can be seen below.
13
15. Figure 8: Final accelerometer configuration. 6 3-axis linear accelerometers
The accelerometers mounted on the hoses would give us insight into the effects of the
hose on the system. Since the peaking behavior is observed after the train begins to brake, we
suspect that the inertia in the hoses and the forces applied by the cars may cause the assembly
to bunch up and peak. Using the accelerometers to capture the behavior of the hoses will
provide useful insight into the cause of this peaking behavior.
Another critical point to observe in the system is the crimp used to join the hose to the
solid metal gladhand. We chose to use this point because the system is rigid from the center of
rotation to the mounting point of the accelerometer. The distance from the center of the
gladhand assembly can be measured and used to calculate the torque applied during peaking.
Collecting acceleration data from this point will allow us to calculate the opposing Fy(t) forces
that we believe contribute to this peaking behavior.
Our final critical point to observe is the center of rotation of the gladhand assembly. This
is an important point to collect data because any abrupt upward or downward acceleration at
this point could cause peaking if the hoses don’t follow this motion. We decided to use only one
accelerometer here because the center point should move together until the hoses fully peak.
This saves cost for the final setup.
14
16. Once we had chosen the type of accelerometer we wanted to use and where we wanted
to locate them on the assembly, we needed a way to fix the accelerometers to the assembly.
We decided to use double sided 3M Urethane Foam Tape 4318 to adhere the accelerometers
to the testing rig. This allows the accelerometers to be easily removed and reused between
tests. The foam tape can be cut into the 1.5” strips needed to adhere each accelerometer in
place. Foam tape is ideal here because it will conform to the curvature of the hose and
gladhand crimp. It will also conform to the irregular geometry of the glandhands at the center of
rotation.
Results
__________________________________________________________________________
The final gladhand placement is shown in figures 9,10,11, and 12 below. The gladhand
were numbered by their corresponding sensor ID for data tracking in the output tables. As
decided, one accelerometer was placed on the center of rotation, one on the clamp, and one on
the hose. Exact placements are given in table 4.
Figure 9. Left hose with the accelerometers.
15
17. Figure 10 . Right hose with the accelerometers.
Figure 11. Front view of the hoses with the accelerometers.
Figure 12. Front view of the gladhands with the accelerometers.
16
18. Black Grey
Sensor # ID Code Distance
From
center of
rotation
Sensor
#
ID Code Distance
from
center of
rotation
1 167845 IMFFUF 0 in. 4 167848 IMWHOR 0 in.
2 167846 IMKXSJ 4 in. 5 167837 IMQAVX 4 in.
3 167847 IMQPQN 11 in. 6 167844 IMZNWB 11 in.
Table 4. Specification of the sensors on both hoses.
Table 4 gives the sensor information and their respective distances from the center of
rotation as a reference to the images with sensor placement. This information can be used to
select the appropriate accelerometer reading and derive the applicable force.
After placing all of the accelerometers on the hoses and installing the USB receiver into
the computer; the group started doing random tests to check if the accelerometers worked
correctly. However, the group used a basic program to connect the sensors to the receiver. As a
result, there were some limitations to the number of heartbeats per minute and controlling the
graphs of the data in the program itself. Therefore, the group did a random test and table 5
shows the sample data taken from the receiver.
17
19. Table 5. Sample Data from the Accelerometers.
Figure 13 shows the data received from sensor 5. The data shows that sensor five
experienced an average reading in the z-direction of 0.98 G. The readings also show sensor 5
experiencing similar acceleration in the x and y direction. This is due to the orientation of the
sensors on the hose and the placement of the hose during the sample experiment.
Figure 13. Sensor 5 data where acceleration in three axises versus time
Data was recorded by the six sensors for about 3 hours. This data was then exported
from the iMonnit website and divided into accelerations by axis. As a result, the three figures 14,
15, and 16 show the x,y and z axis accelerations, respectively. Figure 14 shows that sensor 4
had the highest acceleration in x axis and sensor 5 had the lowest. Figure 15 shows that
sensor 2 had the highest acceleration in y axis and sensor 1 had the lowest. Figure 16 shows
that sensor 6 had the highest acceleration in z axis and sensor 5 had the lowest. However, each
sensor showed a relatively steady acceleration across the 3 hour sample period. This shows
that the accelerometers are working properly. The small errors can be attributed to errors in
18
20. orientation since a level was not used when the accelerometers were adhered to the hoses.
Furthermore, the data doesn’t represent a real life scenario because the results are from a
stationary hose over three hours.
Figure 14. All sensors accelerations in x axis versus time
Figure 15. All sensors acceleration in y axis versus time
19
21. Figure 16. All sensors acceleration in z axis versus time
20
22. Cost Analysis
__________________________________________________________________________
Item Number of Units Cost Totals
Accelerometers 6 60$/ unit 360 $
Transmitter 1 49$/ unit 49 $
Adhesive Tape 1 18$/ unit 18 $
Software 1 - -
Total 9 427 $
Table 6: Cost analysis table.
The total cost for the components used for this design came to approximately $427.00.
Given the customizability of these components and the relatively simple attachment, this design
comes in at a fairly low cost. There are a wide variety of torque meters out on the market
ranging from tens to hundreds of dollars, however, none of these devices would be able to
attach and measure the point in question on the gladhands due to their irregular shape. This
would complicate their design and amount to higher costs due to specialty apparatus’ needed to
attach the sensors to the system.
Additionally, if the company wanted to use wired accelerometers, there are much
cheaper sensors out on the market. We chose to use the wireless transmitters however
because this makes the component assembly far easier, and also allows for a broader range of
application. Should Union Pacific choose to integrate this type of sensor system onto one of its
trains, it would be able to plug the signal receiver into the onboard computer systems and
receive in service data without having to design any special wiring system.
21
23. Not only is the monetary cost relatively low, but the intellectual complexity is also
simplified in the accelerometer design. Simple adhesive and measurement skills are all that is
needed, and there is no complex assembly required. The layout of the sensors is fairly intuitive,
and they are easily assembled. Although the direct reading is not a force, a simple code that
processes the data down allows for direct measurement.
22
24. Sample Calculation
__________________________________________________________________________
The acceleration data received from the sensors can be converted to force and then
converted again to torque using Matlab or any similar coding program. This is achieved by using
the following calculation steps. First, convert units from acceleration in G to inches per second
squared by using the following converting factor:
1 g = 386.1 in / s^2
Then, use Newton’s second law to get the force from the acceleration since the mass is
a constant throughout the process.
F = m * a
Where:
F: Force in pound force (lbf).
m: Mass of the hose in pounds (lb).
a: Acceleration in inches per second square (in/s^2)
Finally, calculate the torque using this equation and the calculated forces:
T= r * F * sin(theta)
Where:
r: half distance between two sensors in inches (in)
F: Force in pound force (lbf)
theta: Angle between the force (F) and the distance (r).
Using Microsoft Excel, the raw exported data was separated by axis and then used to
calculate the data shown in Table 7. Figures 17 illustrates the torque results of the sample
experiment. The data shown is of sensors 5 and 2, where the axis of interest is the z-axis. The
23
25. data shows there is a small change in torque between the two sensors,and the resulted graphs
are similar to the acceleration graphs which proves that the only parameter affecting the torque
is the acceleration. Therefore, the sensors work as expected and with a more efficient data
measurement, and by using an environment similar to the real environment.
Table 7. The calculated force and torque data for sensor 5.
Figure 17. The torque data of sensors 2 and 5 plotted versus time.
24
26. Conclusion
__________________________________________________________________________
This report has discussed the design approach to make an accurate test of hose failure
in a railroad air brake gladhands. The objective of this project was to design a setup of an
experiment to exam and analyze the behavior of a gladhand of an air hose which is to be used
as an air brake for Union Pacific trains. The objective was met by using three tri-axis linear
accelerometers on each side of the gladhand attachment. Although the hose assembly with the
sensors has not yet been tested in the Union Pacific test rig, preliminary testing shows
promising results from the accelerometer data.
Through manual shaking the gladhands from the ends of the sections, varying and peak
accelerations can be observed and the resulting forces and torques can be calculated via a
MATLAB program by utilizing Newton’s Second Law. The accelerations shown in this report are
only used as a proof of concept, and do not actually represent peaking forces of hoses in
service.
The data acquisition was limited to the software application that was included with the
sensors and transmitter. The processing package works on a basis of “heartbeats” for data
transmission. In the package that is included for free the minimum heartbeat was 10 minutes.
That is, only once every 10 minutes will the transmitter ship out its data package for that period.
The description of the sensor package states that the sensors take nearly 500 data points per
second, and it was expected that this entire profile is what would be exported. However, with the
basic software it appears that only the peak values with a few intermittent points are reported in
the heartbeat package. The paid software has heartbeat periods down to the second, which
would result in far more data points and a broader characterization of the system. However,
25
27. because the basic package still transmits peak accelerations, this could potentially still be used
to derive peaking forces in the assembly.
Future Direction
__________________________________________________________________________
The disconnection of the gladhands is a problem where many solutions might be
applicable depending on the way it is being viewed. The causes of the separation might differ,
however the solutions to the problem lead to understanding how much the cause affects the
gladhand separation. Using the accelerometers on the gladhands is one of the applicable
solutions in which the basics of engineering are applied such as Newton’s second law and the
torque-force relation.
Due to the limited amount of time in this analysis, this design is susceptible to upgrades
in which the accuracy and the efficiency will be increased to a better level than the discussed
design.
First, the adhesive used to mount the accelerometers is the Urethane Foam Tape,
shown in figure 18 and the tape works as expected however due to the difference in dimensions
of both the accelerometer and the tape, the accelerometers do not line up perfectly with each
other. The adhesive tape is ¼ inch wide where the accelerometer is approximately 1x1.7 inch,
therefore the adhesive tape is not wide enough to hold the accelerometer. There are a couple of
possible solutions to this problem, one is to use a wider adhesive tape or using a clamp that
could hold the accelerometers. Stress calculations and pricing for the clamps were provided, but
their use was determined unnecessary for the initial testing.
26
28. Figure 18. The adhesive foam tape used to mount the accelerometers
The software used in the design is only a limited version that limits the configuration of
the sensor network. The free version sends one data point only where the express version of
the software is adjustable to whatever the limit of the sensors and the accelerometers are. The
free version provided by the company Monnit is called the Monnit Gateway Application, and the
pro version, which costs around 39$/year to activate, is called iMonnit Premiere. Moreover, the
iMonnit Premiere software supports 5 wireless gateways and 20 wireless sensors, table 8
shows a comparison between the basic and the premiere versions of the software. As shown on
the third column of the table, the software iMonnit Enterprise overtake both the basic and the
premiere, however, the cost is too high compared to the rest of the features otherwise it would
be a good choice. Also, the premiere software could be used as a start then settle on the
iMonnit Enterprise for the on the field measurement taking.(Monnit Corp. 2009).
27
29. Feature Basic Version iMonnit Premiere iMonnit Enterprise
Cost Free 39$/ year~799/year$ 599$~25000$
Minimum Heart Beat
( sensor check in)
2 Hours 10 minutes 1 second
Number of networks
supported
1 20 Unlimited
Number of sensors
supported
500 per network 500 per network 500 per Network
Number of gateways
supported
100 1000 Unlimited
Number of users
supported
1 Unlimited Unlimited
Sensor History Storage 45 days Unlimited Unlimited
Table 8. A feature comparison of the iMonnit Basic, Premiere, and the Enterprise software versions.
Copyright 2009-2015 Monnit Corp.
28
30. References
___________________________________________________________________________
- Budynas, R. G., Nisbett, J. K., & Shigley, J. E. (2011). Shigley's Mechanical Engineering
Design (8th ed.). New York: McGraw-Hill.
- Mabie, H. H., & Reinholtz, C. F. (1987). Mechanisms and Dynamics of Machinery (4th
ed.). New York: John Wiley & Sons.
- Industry, B. (n.d.). Monnit Wireless Accelerometer - G-Force Snapshot - Commercial Coin
Cell Powered. Retrieved November 02, 2016.
- "Safety Brief." (n.d.): n. pag. Triodyne. Triodyne Inc., Dec. 2002. Web.
- "V-band Clamp." SpringerReference (n.d.): n. pag. Normaamericasds. FiveStar. Web.
- "3M Tapes & 3M Adhesives." . 3M, n.d. Web. 02 Nov. 2016.
- Monnit Corporation. ( 2009 ) Monnit Wireless Sensor Network Monitoring - Feature
Comparison. Retrieved fromNovember 28, 2016 from
http://resources.monnit.com/content/documents/brochures/m0015-Monnit-Wireless-Sensor
-Monitoring-Overview.pdf
- Union pacific. (2016) Glad Hand Force Measurement Device. Retrieved from a pdf
file.
- Foam Tapes [online image]. (2016) Retrieved November 28, 2016 from
http://solutions.3m.com/wps/portal/3M/en_US/Adhesives/Tapes/Products/~/Foam-T
ape?N=8302947&rt=r3
29
31. Appendix
_________________________________________________________________________
APPENDIX A: Statement of Work
The University of Nebraska - Lincoln
Mechanical and Materials Engineering Capstone Project
Air Hose Attachment
Adam Elwood, Ismail AL Hooti, Hamood AL Rahbi, Layne Krahn, Taylor Kerl
Introduction
Students from the University of Nebraska - Lincoln in partnership with a team from the
Locomotive Engineering and Quality - Mechanical branch at Union Pacific will develop
the design of an air hose attachment that will allow Union Pacific to measure the
characteristics, specifically torque and peak forces, that cause the attachments to come
unhinged during service. This design will be apart of the Mechanical and Materials
Department capstone project for the Mechanical Engineering curriculum.
Period of Performance
September 2, 2016 - December 2nd, 2016
Student Deliverables to Union Pacific
Kickoff: September 2, 2016. Meeting at Union Pacific for project overview and
discussion.
30
32. Preliminary Design: Students will develop a first pass solution that encompases
key design parameters to present to engineers at Union Pacific for feedback and
redirection if necessary. The preliminary design proposal will include high level
SolidWorks drawings as well as relevant research leading to a design solution.
Critical Design: Students will take feedback from the preliminary design proposal
to develop a final component design for Union Pacific to investigate. The critical
design proposal will include detailed SolidWorks drawings as well as expected
device results and any relevant calculations.
Reporting: A full design report will be produced by the students detailing the
process taken to reach the critical design solution. This report will include the
deliverables from the preliminary and critical design reports as well as a usage or
development plan for Union Pacific to take forward to implement the proposed
solution should they choose to do so.
Key Design Parameters
-Real Time
-Non-Invasive
-Torque and force derivations from accelerometer data
-Dynamic force (instantaneous or peak to peak).
-Tolerances (exact or relative).
31
33. APPENDIX B: BILL OF MATERIALS
Bill of Materials
Item Quantity Cost Purpose
3-axis linear
accelerometers
( monnit wireless
accelerometers)
6 ~60$/unit
+ 40$ Software
subscription
(if needed)
Measures the angular
velocity difference
Adhesives (Urethane
foam tape 4314)
1
(17 yards)
~18$/unit Mount the
accelerometers
Transmitter 1 ~50$/unit Collects data
Clamps 4 ~15$/unit Hold the
accelerometers and
the hose and the
glad-hand
Figure 19. The bill of the materials needed for the hose failure experiment.
APPENDIX C: CLAMP ATTACHMENT
Figure 20. The accelerometer clamp dimensions.
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34. APPENDIX D: CLAMP ATTACHMENT DESIGN
The tests have gone as expected with some design difficulties and got solved by using
some sources. The static test shows in figure 21 that the accelerometer clamp has a minimum
factor of safety 2.625 under a 100 lbf with some part of the design that has a higher factor of
safety which can be noticed on figure 20 by green spots
.
Figure 21. Factor of safety for the accelerometer clamp.
Minimum factor of safety is shown as 2.625.
Moreover, the statics test shows the distribution of Von Mises stress of the
accelerometer clamp. Figure 22, represents the stress distribution in the clamp which shows the
average stress in the design is 9.251*10^(-6) psi but there are some stress concentration
around the locks fillets which reach between 634.8 psi and 1270 psi due to the holding of a
large pressure by the clamp.
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35. Figure 22. Von Mises stress distribution for the accelerometer clamp.
APPENDIX E: GLADHAND DESIGN (FOR SIMULATION)
Figure 23. The basic design of a gladhand.
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