Tests in tension-torsion conditions with descending sections of strain curve construction

The paper is devoted to theoretical and experimental investigation of materials behavior onpostcritical deformation stage (strain softening). Tests results, which confirm theoretical justification ofspecimen configuration impact on the possibility of creating descending sections of strain curve, are given. It isshown that, with sufficient stiffness of loading system, equilibrium postcritical deformation of materials ispossible. It is confirmed in uniaxial tension tests with unloading on postcritical deformation stage. Test resultson tension with torsion of thin-walled tubular specimens in strain softening conditions are adduced

Relay-race deformation mechanism during uniaxial tension of cylindrical samples of carbon steel: using digital image correlation technique

The work deals with experimental study of macro localization of plastic yielding occurrences of structural carbon steel, research of singularity of deformation wave processes by complex use of contemporary test equipment and high effective digital image correlation method. Evolution of nonuniform axial strain fields on surface of cylindrical samples during uniaxial tension was registered, time dependences were drawn, and a ‘relay-race’ mechanism of material deformation was found out at the stage of yield plateau forming. Strain concentration ratio was estimated for several material deformation stages