Analysis of Cantilevered Aluminum C-Beam Using Engauge Digitizer
Objective:
Compare the experimentally measured deformed shape of a beam to the shape calculated by finite
element analysis
Description of Model:
A gridded mat was bolted onto a sheet of plywood which was then bolted to a pre-threaded steel base.
A level was used to ensure that the horizontal gridlines were parallel to the floor and that the mat itself
would be perpendicular to the floor. The grid assembly was attached to a cart to ease positioning of the
grid. An aluminum channel with cross-sectional dimensions shown in Fig. 1 was embedded in a wooden
support as shown in Fig. 2. Solid lines in Fig. 1 represent the channel while dashed lines represent the
threaded rod which is used to load the channel.
Fig. 1: Cross Section of Aluminum Channel
Fig. 2: Beam Supports Mounted on Cart
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Steel-reinforced epoxy putty was applied to the base to prevent rotation of the beam within the base.
The beam was mounted with other beams on a cart that enabled mobility of the model but at the
expense of being a less ideal support. The beam and the grid assembly were positioned as shown in Fig.
3. The beam was loaded by suspending two 5-lb weights onto the threaded rod as shown in Fig. 4. The
load offset was measured using a caliper as shown in Fig. 5 and subtracting half of the beam and wire
thicknesses.
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Fig. 3: Unloaded Beam
Fig. 4: Loaded Beam
Fig. 5: Load Offset Measurement
Results:
Fig. 6. shows the deflections from the case in which the beam was mounted to a table top. The results
from the cart mounting are shown in Fig. 7.
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Fig. 6: Results from Tabletop Mounting
Vertical Displacements While Mounted On
Table
Vertical Displacement (in.)
0
-0.2 0
10
20
30
40
-0.4
-0.6
Measured Using Engauge
Digitizer
-0.8
-1
Finite Element Prediction
-1.2
-1.4
-1.6
-1.8
Distance Along Beam (in.)
Fig. 7: Results from Cart Mounting
Vertical Displacements While Mounted
on Cart
0
Vertical Displacement (in.)
0
10
20
30
40
-0.5
-1
Measured using Engauge
Digitizer
-1.5
Finite Element Prediction
-2
-2.5
Distance Along Beam (in.)
Recommendations/Future Actions:
It is likely that the support of this beam cannot be easily modified to become more ideal. The base of
the current model and the mounting technique allow flexion that cannot be easily measured using
Engauge Digitizer. Time would be more efficiently spent developing a different model. Currently,
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experimental set-ups are being investigating which would be mounted within a frame structure. The
frame structure would provide more idealized support and allow mounting of instruments to measure
displacements as well as reaction forces. These concerns could be addressed by creating an experiment
similar to the model shown in Fig. 8.
Fig. 8: Inspiration for Improvement or Recreation of Model
Relevant Files and Documents:
Results and Reports, End of Summer\Cantilevered Aluminum C-Beam\Engauge Digitizer Files
Results and Reports, End of Summer\Cantilevered Aluminum C-Beam\Photos
Results and Reports, End of Summer\Cantilevered Aluminum C-Beam\CBeam.cae
Results and Reports, End of Summer\Cantilevered Aluminum C-Beam\ Cantilevered C-Beam.xlsx
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