Specifications

CT Corsair Final Report May 2, 2014
33
8.4.2 Analysis Criteria
The program used for analysis was ABAQUS CAE
1
. When compared to ANSYS, another option
for FEA, ABAQUS provides better meshing capabilities and a user-friendly interface more
intuitive to a new user than ANSYS
8
. In order to achieve accurate and usable results, it was
imperative that appropriate inputs were provided including material properties, boundary
conditions, loading scenarios and meshing and mesh convergence. These inputs are outlined in
the subsections below.
Material Properties
The material used to manufacture the upper scissor arm was 6061 Aluminum. The relevant
material properties of this material include a Young’s Modulus of 69x10
9
69 and
Poisson’s Ratio of .33.
29
These properties were assigned to all parts of the upper scissor arm as it
was all manufactured using the same material.
Boundary Conditions
The boundary conditions used in the analysis were difficult to determine, as the decision was
made to exclude the pins from the analysis. This created a challenge regarding fixing one end of
the member in order to constrain it from rotating or moving about the x, y, and z-directions. To
determine the quality of the chosen boundary conditions prior to analysis, three working
engineers were consulted as resources
8
. The most accurate way of performing the analysis was
discovered to be through fixing one set of bearing holes. The holes were fixed on one half of the
surface, as only that half would be in contact with the pin during compression. This is depicted in
Figure 36.
Loadings
The majority of an effective and accurate FEA depended on understanding the way that the
component was loaded, therefore determining the way the member deformed at failure. The
member is subjected to a compressive force that acts on the bearings, which indicates a bearing
stress scenario. This loading can be summed up using the bearing stress equation:
(Equation 17)
Where is the surface area of the hole, or in this case the diameter of the hole being multiplied
by the thickness of the hole and is the load magnitude. This loading is shown in Figure 37.
Z
X
Y
Figure 36. Bearing stress contact surface in Abaqus