Abstract
It has been problematic to find the directions of bifurcating paths with reference to the critical eigenvectors when the multiplicity of criticality is large. Stiffness modification method, which slightly modifies tangent stiffness matrices to separate the multiple eigenvalues, is a pertinent means for this problem. However, appropriate modification of stiffness matrices has not been clarified and the critical eigenvectors required for searching bifurcation paths cannot be obtained by the stiffness modification method. In this context, through a set of bifurcation analyses of a periodic honeycomb structure, we examine an appropriate modification of the stiffness matrix and how to obtain a set of critical eigenvectors with certain symmetries corresponding to directions of the bifurcating paths.
