8 Pages

Theoretical Model for Calculating the Twist of a Piezoelectrically Actuated Supersonic Missile Fin

WithR. McBride, M. Price, E. Benard, A. Murphy, A. Gibson

A theoretical model for calculating the performance of a piezoelectrically actuated supersonic missile fin has been formulated and is presented. Conventional fin actuation methods use hydraulics/electromechanical systems mounted within the missile body. A piezoelectrically actuated system may be used to replace these conventional methods requiring only a voltage source and a feedback loop for control. The piezoelectrically actuated system offers a combination of a reduction in weight, size and complexity resulting in increased performance. The theoretical model formulated considers a piezoelectrically actuated plate mounted within a supersonic fin such that when the piezoelectric actuators are operated, due to the orientation of the piezoelectric actuators on the plate, a span-wise twist is excited in the missile fin. The twist induced in the fin may be used for aerodynamic control of the missile and the degree of twist is controlled by regulating the driving voltage to the actuators. The theoretical model initially predicts the performance of the piezoelectrically actuated centre-plate using a combination of Classical Laminate Plate Theory and mathematical approximations. The supersonic fin is then included in the model and Bredt-Batho theory is used to calculate the behaviour of the complete fin structure. A case specific analysis is conducted on a 10% t/c supersonic fin and the results obtained from the theoretical model are compared to a Finite Element Analysis of the structure. For a range of fin skin thicknesses, predicted theoretical and Finite Element Analysis values of twist are within 1.5%