Flutter Analysis of Missile Control Surfaces Containing Structural Nonlinearities

Abstract

Missile control surfaces often contain nonlinearities which affect their performance characteristics and flutter boundaries. Analysis techniques accounting for these nonlinearities and an understanding of their potential influence on the flutter mechanism greatly increase the efficiency of the control surface design process. This paper presents such analysis procedures and discusses their application to the investigation of the dynamics of missile control surfaces containing structural freeplay-type nonlinearities. The problem discussed deals with a missile control surface exposed to subsonic flow. Nonlinearities are associated with freeplay in the root support stiffness. Definition of the loads acting on the control surface uses a simplified aerodynamic representation. The basic assumption of this approach is that the lift force is proportional to and in phase with the torsional, or pitch, motion. Both rigid and flexible control surface configurations have been examined with nonlinearities in either one or both of the root pitch or roll degrees-of-freedom.