Specifications

CT Corsair Final Report May 2, 2014
32
Figure 34. Side plates of upper
scissor arm modeled in Solidworks
expected. Therefore, the arm will either fail in buckling or at the bearing holes due to yielding
5
.
8.4 Upper Scissor Arm: Finite Element Analysis
8.4.1 Model Selection
Prior to analysis in ABAQUS, it was crucial to ensure the upper scissor arm drawn in Solidworks
included every detail of the member including the internal support pins. Through observation of
the model and understanding of the finite element analysis (FEA) software it was determined that
the model could be simplified. Initially, there were three points of interest to consider in the
upper scissor arm analysis
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:
1. The welds connecting the plate to the member
2. The pins at each end of the member
3. The plates on each side of the member
The total member is shown in Figure 33 with just the plates shown in Figure 34.
Of the three points of interest, it was determined that the welds would be the most difficult to
model. To model these points the material properties needed to be altered around specific
sections, which complicated analysis. The welds are not interfering with the location that the
load is being applied or the area that the member is fixed therefore the decision was made not to
model the welds in SolidWorks and ABAQUS. Although the decision affects the analysis results,
there will not be a drastic difference.
The second point of interest were the pins that sit in the bearings which allow the arms to pivot
about a point. Too assess if the pins were necessary in the FEA model, the load distribution
between the pins and member was explored. The load is transferred through the pins only at the
location where the pin is in contact with the member. Assuming that the majority of the load is
then transferred onto the bearing hole surfaces rather than the pin itself, the pins can be safely
removed without drastically impacting the results of the FEA analysis. The area where the force
will be distributed is shown in Figure 35.
The third point of interest in determining the model used for FEA are the plates on either side of
the upper scissor arm. These plates are welded to the member on either side and provide extra
support to the member during loading. Since it is unknown how both loading cases will be
impacted by keeping or removing these plates, two models were created; one with the plates as
part of the solid model and one without.
Figure 33. Entire upper scissor arm
modeled in Solidworks
Figure 35. Bearing stress area shown in
Solidworks model