Specifications

CT Corsair Final Report May 2, 2014
36
Figure 43: SolidWorks Model of Lower Scissor
Arm
8.5.2 Finite Element Analysis: Model Selection and Criteria
After the lower scissor arm was designed, it was necessary to
perform finite element analysis on it in order to confirm that
it can support the weight of the simulator as well as other
combining forces. To begin the analysis, a free body diagram
was used to visualize how the forces would act upon the
simulator. The same free body diagram shown in Figure 31
can be used, only with the compressive forces in the two-
force member reversed to represent the tensile forces on the
scissor arm.
After reviewing the free body diagram, we chose to model the arm under tensile stress at each
end as we found that the arm would fail first due to tensile or compressive stresses at the bearing
holes rather than to bending near the spring force. The forces being applied are very similar to
the forces that acted upon the lower scissor arm earlier in this report. Therefore, the analysis
would be carried out in a very similar manner as well. Keeping in mind that the arm was
analyzed in tensile stress, it was found that we could also perform a real tensile test on a quarter
scaled scissor arm in order to verify that we were performing our analysis correctly.
The material chosen to design the scissor arms with was Aluminum 6061-T6. This material is
similar to the one that the lower scissor arms are made of, and we assumed that it would be
strong enough to support all of the forces acting upon the newly designed scissor arm. If, after
the analysis, it were not strong enough, a new material would be chosen in accordance with the
analysis. The properties mainly looked at in our design were the tensile yield and ultimate
strength, Young's Modulus, and the Poisson ratio. These values can be seen in Table shown
below:
Property
Value
Young’s Modulus
68.9 GPa
Poisson’s Ratio
0.33
Tensile Yield Strength
276 MPa
Ultimate Tensile Strength
310 Mpa
Table 8: Properties for Lower Scissor Arm Analysis
8.5.3 Analysis Results
The newly designed scissor arm was analyzed in tension using ANSYS software to perform the
analysis using the loadings as shown in Figure 44.
Figure 44. Lower Scissor Arm Loading in ANSYS