Tailgate Design Project
DEPARTMENT OF FOOD, AGRICULTURAL AND BIOLOGICAL ENGINEERING
Adam Andrews, Mauricio Nieto, John Walter and Erich Widmer
RACT
Inc. has commissioned a design of a tailgate station for
avid tailgate fan and everyday camper. The station,
d to be maneuverable without the use of a vehicle,
a custom stainless steel 4-burner grill with propane tank
insulated cooler, table space on either side of the grill, and
pace for all storage needs. Because the unit must be
nough to tow behind an automobile, much attention was
weight distribution relative to the trailer axels, and a
h road test was designed to ensure driving safety of the
Figure 1 shows the framing for this unit. Due to the lower tensile
strength of aluminum compared with stainless steel the unit framing
was overdesigned.
CALCS, SIMULATIONS, TESTING AND RESULTS
WEIGHT DISTRIBUTION
Completion of the tailgate station model in SolidWorks showed the
COG located at 23 inches from the rear of the unit. After adding in
the additional weight of the grill the COG location changed to
22.25 inches. As this is just a recommendation, it was decided to
go forward with design of the tailgate station. Figure 6 shows the
completed tailgate station with the grill installed and all
compartments empty.
In addition to COG, tongue weight needed to be measured. The
following method was used in verifying allowable weight:
• A cinder block placed under the tow bar to simulate hitch height
• Borg scale placed between blocks and tow bar
• Scale read 40 lb
ODUCTION
, Inc. is a sheet metal fabrication company located in
Ohio. They specialize in Computer Numerical Control
machining, laser/water cutting and welding/fabrication.
TW =
CTIVES
e
ht weight
mpact Size
od storage capacity
oking capacity
sy to operate
neuver with/without a vehicle
GN
selection was critical due to the 1090lb weight restriction
aul master trailer purchased to support the unit. (Harbor
ols, 2015) The material selected would need be durable and
ght. Stainless steel was initially chosen because of its low
t after applying the SolidWorks mass properties tool it was
red that the overall weight for this unit was between 850herefore, the material was changed to aluminum alloy,
rovided a much lighter unit at 236lb. A comparison of these
erials was conducted to support this decision.
4 Annealed Stainless Steel (SS):
Density  7.90 g/cm^3
Strength to Weight Ratio (S2WR)  71 kN-m/kg
Ultimate Tensile Strength (UTS)  560 MPa
Yield Strength (YS)  230 MPa
Figure 1: 1”x1”x1/8” 6061-T6 Aluminum Tubing
Given the clients design criteria it was determined to locate the grill
centered along the rear of the unit. This location was selected in an
effort to maintain the recommended center of gravity (COG). The
grill selected specifies it’s weight to be 100lb. (Great Grill, 2015) Due to
the large weight at the rear there were concerns with tilt while the
trailer is unhitched and exceeding the tongue weight while hitched.
NOTE: DRAWER, TABLE, STORAGE DOORS SYMMETRICAL
FEA ANALYSIS
Integrated Finite Element Analysis (FEA) simulations were
conducted using SolidWorks software to provide real life data
concerning applied loading on the unit and thermal heat transfer
through the unit. Results from these tests are provided as follows:
DISTRIBUTED LOAD
A 100lb distributed load simulation was applied at the grill location.
Since the framing around the grill consists of longer tubes it was
determined that the results from this analysis would be sufficient to
conclude that the yield capacity of the compartment framing would
meet the necessary required yield.
Figure 6: Picture of completed Tailgate Station
CONCLUSIONS
COOLER
PROPANE
HOSE
PORT
Figure 3: FEA results of applied distributed load at grill location
Figure 3 shows a diagram on the left that indicates where the 100lb
distributed load was applied. Refer to Figure 1 for additional
clarification. The undulation in the bars is an exaggeration of the
tensile stresses. The scale to the right shows that the yield is
approximately 2.736e+006 N/m^2 at these locations and does not
exceed the yield stress of 2.750e+008 N/m^2.
STORAGE
(Makeitfrom, 2015 and Burnsstainless, 2015)
GRILL
LOCATION
TABLE
DRAWER
Figure 2: Tailgate Station design with overall dimensions
The FEA thermal analysis results shows the worse case scena
after using the grill for 4 hours. The highest temperature of 303
remains localized at the grill. Therefore, the only concern in re
heat transfer is radiation from the surroundings. Please see ha
provided for heat transfer due to radiation.
∗ 100 = 11.9%
Recommended weight distribution as follows:
•
60% of weight in front of the axle
•
40% of weight behind the axle
•
10-15% total weight (tongue weight) (eTrailer, 2014)
61-T6 Aluminum alloy was selected:
Density  2.70 g/cm^3
Strength to Weight Ratio (S2WR)  115 kN-m/kg
Ultimate Tensile Strength (UTS)  310 MPa
Yield Strength (YS)  270 MPa
g 6061 over S.S. results in a loss of UTS, but this loss is
n YS and more importantly S2WR. The gain in S2WR is
nt due to the weight restriction. 6061 is stronger compared
same weight of SS.
–
40
336
Figure 4: FEA results of heat transferred through unit
THERMAL ANALYSIS
Insulation strips were installed between the grill and unit to maintain
control of the overall temperature. The thermal analysis simulation
in Figure 4 provides heat transfer data over the course of 4 hours.
As evidence by these results the heat stays concentrated at the grill
location. This indicates that the material selected provides the
necessary dissipation required in order to minimize safety
concerns.
Installation of the grill at the specified location did not result i
tilting. The designed frame successfully supports the grill, the
it can be concluded that the framing at the compartments wil
support upwards of 100lb. Thermal analysis results show tha
is no concern in regards to heat conduction occurring at the
from the grill. Any inconclusive results regarding calculations
simulations have been validated after successful execution o
road tests, which consisted of speed bumps, braking, turning
speeds of at least 35mph. In conclusion this design is sound
even with the challenges encountered during design and
fabrication both the OSU Tailgate Design Team and Lochard
that this prototype is a success and a good model from which
mass production will produce better designs for future units.
BIBLIOGRAPHY
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Makeitfrom.com, (2015). Compare Materials. [online] Available at: http://www.makeitfrom.com/comp
T6-Aluminum/Annealed-304-Stainless-Steel/ [Accessed 15 April 2015]
Burnsstainless.com, (2015). Stainless Steel. [online] Available at: http://www.burnsstainless.com/stainl
eTrailer.com, (2014). Trailer Hitch Receiver Sizes. [online] Available at: https://www.etrailer.com/faq-hit
Harbor Freight Tools,. '1090 Lb. Capacity 40-1/2 In X 48 In Utility Trailer'. N.p., 2015. [Accessed. 13 Mar.
Great grill, great price et al. 'Kitchenaid 4-Burner Built-In Propane Gas Island Grill Head In Stainless Stee
Rotisserie Burner-740-0780 - The Home Depot'. The Home Depot. N.p., 2015. [Accessed. 13 Mar. 2015]
ACKNOWLEDGEMENTS
•
Lochard Inc.
www.lochard-inc.com