ideal plasticity, flat problem, orthotropic semispace, ellipsoid anisotropies, pressure of a flat stamp. 

The problem about pressure of a flat stamp on orthotropic ideally plastic semispace is considered. Dependence of pressure of fluidity on a direction of the main pressure is set by ellipsoid anisotropies. The angular point of a stamp and rectilinear boundary of semispace generate the aligned fan of rectilinear characteristics, as well as in case of an isotropic body, with similar kinematics of a plastic current. But pressure upon a stamp essentially depends on plastic anisotropy