DETERMINATION OF THE STRESS TENSOR COMPONENTS UNDER NON-MONOTONIC PLASTIC DEFORMATION

Authors

  • Roman Syvak Vinnytsia National Agricultural University
  • Vitalii Ogorodnikov Vinnytsia National Technical University
  • Ivan Syvak Vinnytsia National Technical University

Keywords:

stress, deformations, anisotropy of strain hardening, Bauschinger effect, accumulated deformation

Abstract

The paper proposes application of the model of anisotropically changing body, proposed by G. Backhaus, to determine the stress-strain state in the process of radial extrusion with subsequent upsetting.

The object of the study is  plastic deformation of the body, changing anisotropically under non-monotonic load.

The purpose of the study is determination of the value and regularities of the stress tensor components variations under non-monotonic plastic deformation.

Plasticity theory for the body, that in changing anisotropically, is not suitable for quantitative description of non-monotonic deformation processes. Besides, many material behavior features can be considered as Bauschinger effect manifestations. In order to take these features into account, the corresponding physical equations should be used.

This paper uses the model, proposed by G. Backhaus, for taking into account the anisotropy of strain hardening. Experimental dependencies have been obtained for function , which makes it possible to take into account the inherited influence of deformation history on the current state of material under non-monotonic deformation also for Baushinger parameter b(еu). It has been found that for steel 10 parameter b and function  depend strongly on the accumulated deformation еu for еu≤0,05, and for еu>0,05 these parameters remain practically stable.

For the process of radial extrusion with subsequent upsetting the stress-strain state has been determined in the points located on the horizontal axis of symmetry of the workpiece. For determining kinematic characteristics of the plastic deformation process, an experimental-calculation method of coordinate grids is used. It has been found that non-monotony of plastic deformation has a strong influence on the character of curves describing dependence of stresses on the deformation degree. Application of the procedure, proposed in this work, enables considerable improvement of the accuracy in calculations of stress tensor components and the laws of their variations.

Author Biographies

Roman Syvak, Vinnytsia National Agricultural University

Cand. Sc. (Eng.), Assistant Professor,  Assistant  Professor of the Chair of General Technical Disciplines and Labor Protection

Vitalii Ogorodnikov, Vinnytsia National Technical University

Professor, the Head of the  Chair of Strength of Materials and Applied Mechanics

Ivan Syvak, Vinnytsia National Technical University

Professor, Head of the Chair of Machine-Building Technology and Automation

References

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Published

2015-06-20

How to Cite

[1]
R. Syvak, V. Ogorodnikov, and I. Syvak, “DETERMINATION OF THE STRESS TENSOR COMPONENTS UNDER NON-MONOTONIC PLASTIC DEFORMATION”, ВМТ, no. 1, pp. 111–119, Jun. 2015.

Issue

No. 1 (2015)

Section

Articles

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