Aeroelastic Instability of Flexible Rocket Bodies on the Basis of a Simplified Mechanical Model

The present paper deals with the applicability of simplified mechanical models to discuss the aeroelastic instability behavior of flexible rocket bodies. A suitable mechanical model to demonstrate body divergence and flutter has been discussed and the stability analysis of the model has been presented. The flutter criterion requires a computation of the characteristic polynomial. Sylvester’s dialytic method of elimination is used to compute the required discriminant. A mechanical model composed of three bars, connected together by two elastic rotational springs, having five degrees-of-freedom is chosen for demonstrating both divergence and flutter instabilities. Effects of mass distribution, stiffness distribution, and location of stabilizer fin on instability behavior are discussed.