Application of Numerical Continuation in Aerospace Problems

Abstract

A basic element in the structural design of an aircraft, rocket booster or space craft is the thin walled shell. Shells are applied for their high stiffness to weight ratio, for their high strength to weight ratio and last but not least for aerodynamic reasons.

When compressive loading conditions prevail the load carrying capacity of shell structures is often determined by loss of stability of equilibrium. For these and related problems of nonlinear structural behavior several methods of analysis are available. The most sophisticated tools of analysis are the large scale finite element codes and it is in these codes that the methods of continuation come into play.

Indeed, without path following techniques, the calculation of the loss of stiffness or loss of structural integrity for specific loading conditions can in general not be carried out. We will focus on the scope of a well known finite element code STAGS; a code specifically designed for nonlinear shell analysis. We will give an overview of the path following techniques that are part of this code, including a bifurcation processor. Finally, we will show some practical problems that were solved by it.