This study introduces an aeroelastic model for the linear/non-linear
analysis of thick fins in supersonic or hypersonic regimes. In the first step a linear
aeroelastic model for the analysis of thick fins is developed. To this aim, a thick fin
with two degrees of freedom (2 DOF) as well as an elastic double-wedged fin in
supersonic/hypersonic flight regimes are considered. An unsteady aerodynamic
model is developed based on the shock/expansion theory by local aspplication of
the piston theory over the flat surfaces of the fin. The structural model is also
obtained based on the Lagrangian approach. Employing such developed model, the
effects of initial angle of attack, thickness and some other geometrical parameters
on the aeroelastic stability boundaries and unsteady aerodynamic loads are studied.
In the next step, a more sophisticated model describing the non-linear aeroelastic
behavior of fins with 3 DOF and free-plays in flapping, plunging and pitching
motions is investigated. To this aim, governing equation are obtained by a
modification of the linear model and effects of several geometrical parameters (e.g.
thickness, initial angle of attack, hinge frictional torque etc.) on the aeroelastic
behavior of fins are assessed1.
Keywords: Aeroelasticity, Free-play, Local piston theory, Shock and
expansion analysis, Thick supersonic fin.
