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

  • S. K. Jatav
  • P. K. DattaEmail author
Original Paper


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.


Flutter Divergence Mechanical model Aerodynamic load 

List of symbols

\( C_{L\alpha } \)

Lift curve coefficient

\( L \)

Concentrated aerodynamic load

\( M \)

Concentrated mass

\( S \)

Cross-sectional area of bar

\( T \)

Kinetic energy

\( K \)

Rotational spring constant

\( l_{\text{F}} \)

Location of stabilizer fin measured from tail



\( U \)

Flight velocity

\( V \)

Potential energy

\( \alpha \)

Angle of attack

\( \xi \)

Dimensionless location of stabilizer fin

\( \kappa \)

Dimensionless spring constant

\( \mu \)

Ratio of fluid mass to concentrated mass

\( \rho \)

Density of fluid

\( \tau \)

Dimensionless time

\( \phi \)

Inclination of a bar to horizontal axis X


\( {\text{F}} \)


\( {\text{N}} \)


\( {\text{T}} \)




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Copyright information

© The Korean Society for Aeronautical & Space Sciences 2019

Authors and Affiliations

  1. 1.Department of Aerospace EngineeringIndian Institute of Technology KharagpurKharagpurIndia

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