On stability of biaxial tension of a square plate in a gradient mechanical system

The paper deals with the problem of stability of a biaxial tension process of a square plate made from nonlinear material. The load is applied through two ideal elastic rods. The bifurcation sets and the separatrix of this gradient mechanical system are determined. The stability of deformation process is studied by the method of constructing of the discriminantal cone for the Hesse matrix of the system potential function.