Brittle-rupture mechanisms of axisymmetric plates subject to creep under surface and thermal loadings

The problem deals with analysis of the damage mechanisms of thermally prestressed plates subject to brittle rupture. The rheological properties of the structure are described by the similarity of deviators according to the flow theory, and the time hardening theory coupled with the Kachanov orthotropic brittle rupture equations. Two boundary problems are formulated: the plate prestressed by the elastic ring or by the cylindrical shell. Depending on the values of prestressing parameters two basic failure mechanisms may by distinguished: 1) first macrocracks appear in the middle part of the plate, 2) first macrocracks appear along the periphery of the plate. Optimization of these parameters may lead to the uniform creep strength (double failure mechanism: macrocracks appear in the middle and at the periphery of the plate simultaneously). (author)