4. Methods for determining instability loads

The most frequently used methods for analyzing the stability of conservative systems are:

• adjacent state equilibrium method;

• energy method.

• The adjacent state equilibrium method allows bifurcation instability to be studied. Its implementation involves performing a linear instability analysis. According to this method, we examine whether, along a fundamental loading trajectory, there exists, for the same loading level, a possible adjacent deformed configuration in equilibrium, i.e., a configuration infinitely close to the fundamental configuration under consideration.

  Remember that the value of the load for which such an adjacent equilibrium configuration exists is called the bifurcation load...