*** PAGE IN PROGRESS - NEED PREV. WORK AND CURRENT MATLAB ANALYSIS TO BE ADDED ***
This page contains the analysis work done to prove - to the best of our ability - that the fin can will withstand flight loads. The following effects were considered:
- Aerodynamic moment from angle of attack (Lift & Drag)
- Viscous shear from airflow
- Aeroelastic Flutter
- Thermal effects
- Spinning on the motor case
Lift & Drag
According to thin airfoil theory, we can estimate the CL of a flat plate by the following equation:
CL ~= 2*pi*AoA
where AoA is the angle of attack, in radians. According to the flight simulations, the highest estimated angle of attack is 0.05 radians, leading to a CL of ~0.32. However, to account for adverse effects from the launch tower leading to increased angles of attack, the maximum CL was set to 1. Based on thin airfoil theory, the CD of a flat plate at CL = 1 was estimated at (***0.2?). Next, the lift equation was applied at max velocity and assuming sea level atmospheric density:
Lift = 1/2*rho*v^2*CL*A_fin = ~3000 N
Drag = 1/2*rho*v^2*CD*A_fin = ~600 N
Lift was used to calculate the base bending moment for the fillets, and drag was used to calculate the variation in the moment from the front to back of the fin can.
To resolve the point force into a distributed moment, the lift was divided by the fin length, and a shear/moment diagram was used:
*** Add shear/moment diagram ***
This leads to a root bending moment of ~300 Nm.
Viscous Shear
TODO
Flutter
Thermal Effects
To consider thermal effects
Spinning on Motor Case