Experimental Study of Complex Elastoplastic Deformation of Brass L63 Along Two-Link Broken Trajectories

The article presents the results of an experimental study of complex elastoplastic deformation of L63 brass along two-link broken strain trajectories in the deviatoric strain space. The description of the experimental program, presentation and discussion of its results are carried out in the vector representation of stresses and strains using the terminology and approaches of A.A. Ilyushin’s theory of elastoplastic processes. The experiments were carried out in the mechanical testing laboratory of Tver State Technical University using the automated testing machine SN-EVM under combined loading of thin-walled tubular specimens with axial force and torque (P + M experiments). The loading process was assumed to be isothermal, and the strains were considered small. The material of the specimens was sufficiently isotropic initially, as confirmed by experiments under simple loading. The test programs were implemented in the deviatoric space of strains (rigid or kinematic loading). Two-link broken trajectories with the first link length of 3% and fracture angles of 90°, 135°, and 180° are investigated. Experimental diagrams characterizing the scalar and vector properties of the L63 brass material are presented. Approximations of deformation diagrams under simple and complex loading are proposed. The research results can be used in constructing mathematical models of plasticity theory.