Experimental and theoretical study of the postcritical deformation stage of materials under the various types of loading conditions
Postcritical deformation stage of materials connected to the structural failure and fracturing processes and reflected on the strain curve as a descending section. Realization of the postcritical deformation stage allows using of the reserves of load-carrying ability, increase vitality and safety of the deformable systems. The work is devoted to experimental investigation of the behavior of structural carbon steels on the postcritical stage of deformation under different types of the stress-strain state. The test results of uniaxial tension with various stiffness of the loading system with using of special test tool are obtained. It is demonstrate, that the failure moment of materials corresponds to a point on the descending section of strain curve and depends on stiffness of the loading system. Got results of the behavior of different structural steels on the postcritical stage of deformation under proportional and non-proportional tension-torsion tests at room and high temperature. The methodic of realization of the additional vibrations during quasi-static tension with using of the biaxial test system is proposed. It is shown, that the additional loadings could lead to equilibrium deformation of specimen on the postcritical deformation stage.