NONLINEAR FLUTTER ANALYSIS OF MISSILES WITH PNEUMATIC FIN ACTUATORS

A method for Butter analysis and design of missiles with pneumatic fin actuators is presented, The method combines state-space aeroelastic m odels with nonlinear pneumatic models for time-domain simulations and for frequency-domain approximate solutions, The missile and its fins a re represented by normal modes with the generalized unsteady aerodynam ic force coefficients approximated by rational functions, Time simulat ions are presented for various velocities, maneuver commands, and pneu matic parameters, and the system behavior at the Butter boundary is di scussed. It is shown that the fundamental fin flutter speed is strongl y dependent on the missile maneuver commands. The Butter mechanism is investigated with equivalent frequency-domain modes, A way to increase the flutter speeds by introducing chordwise-bending flexibility near the fin trailing edge is introduced and demonstrated.