PFR - Aerospace Engineering Sciences Senior Design Projects ...

Project Final Report – CUDBF April 30 th , 2009
ASEN 4028: Aerospace Senior Projects
Figure 75: Motor Pylon Strain and Deflection
Next, another COSMOSWorks analysis was done on the stresses applied to the motor, pylon,
balsa insert, and nylon screw assembly to factor in the balsa mount’s material strength. The
results from the entire motor mount assembly analysis are provided in Figure 76. It was
determined that the maximum stress encountered on the balsa insert was only 210 psi. Balsa
wood has a minimum compressive strength of 377 psi, so there is a minimum 1.8 safety factor in
this component. The maximum stress encountered among the four nylon screws was 4.5 ksi.
The yield stress for the nylon bolts is 20.1 ksi, creating a minimum 4.5 safety factor in the bolt
components. Each component was determined to have adequate safety factor built into the
component design, and the motor mount assembly was determined to be structurally sound.
Figure 76: Motor Mount Maximum Stresses
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