Branch switching techniques for bifurcation in soil deformation Original Research Article

The transition from homogeneous to localized deformations during the loading of a soil specimen within a finite element computation is often characterized by a bifurcation point, indicating loss of uniqueness of the solution. The signalling of a bifurcation point is done via the eigenvalues of the structural stiffness matrix resulting from the finite element discretization. Eigenvectors related to negative eigenvalues can be used to perturb a homogeneous state and to obtain a localized deformation mode. This procedure is called branch switching. Several methods are proposed to perform this branch switching.