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12MODELING BEHAVIOR TEXTURED AND NON-TEXTURED ALLOY AT GREAT
DEFORMATIONS
Domichev K.
Kiev International University, professor Chair of Computer Science Candidate of technical sciences Petrov A.
Dnieper National University named after Oles Honchar,
Senior researcher, Chair of Theoretical and Computer Mechanics, PhD
Steblyanko P.
University of Customs and Finance, professor, Chair of Cybersecurity and Information Technology Doctor of Physical and Mathematical Sciences
Abstract
The paper investigates influence of large deformations (up to about 15%) arising from the plastic deformation of martensite on mechanical behavior of textured and non-textured alloy. The problem is considered in a geometrically nonlinear formulation.
Experimental results show that with increasing plastic deformation, the residual deformation increases and the phase deformation curves of the conversion stress from martensite to austenite become steeper and less obvious.
The paper proposes an analytical-numerical approach to describe diagram of material during unloading starting from an arbitrary point of the active site. The approximation of the curve on the corresponding sections of the diagrams is realized by means of a stressed spline.
Keywords: large deformations, pseudo-elastic-plasticity, spline functions, functional materials, geometric nonlinearity.
The work is devoted to the study of structural elements made of functionally inhomogeneous materials at large deformations. Functionally inhomogeneous materials or intellectual materials are widely used in science and technology. One of the representatives of this class of materials are materials with shape memory or materials with the property of pseudo-elastic-plasticity. Their physical or mechanical properties are very different from the behavior of conventional structural, heat-resistant or tool materials. Mechanical behavior largely depends on external conditions (temperature, pressure) and the history of their change.
Materials with shape memory (MPF) are able to accumulate deformation at low temperatures under load, and after heating to fully or partially restore it. Such materials include primarily alloys in which reverse martensitic transformations develop under thermal or mechanical action. These alloys can be the basis of composite materials, to a greater or lesser extent capable of restoring shape.
A similar phenomenon of shape change is observed in polymeric materials. However, the nature of deformation in them and the conditions of its creation and implementation are significantly different from alloys with shape memory.
The main mechanism in these processes is the inverse martensitic transformation between the phases of the solid, which can occur with a relatively small change in temperature. This conversion can be caused by a change in temperature or a change in voltage.
Materials that have the properties of shape memory, pseudo-elasticity and pseudo-elastic-plasticity usually include the following: NiTi AgCd, AuCd, CuAlNi, CuSn, CuZn, FePt, MnCu, FeMnSi, CoNiAl, CoNiGa, NiPe , NiTiNb, NiMnGa.
Investigation of the influence of large deformations (up to about 15%), which arise from plastic deformation of martensite, on the mechanical behavior of textured and non-textured alloy. The schematic diagram of the material before and after the phase transformation is shown in Figure 1. Note that in [1] the behavior of pseudo-elastic-plastic material at deformations up to 6% was studied. In this case, residual deformations during unloading were absent. The corresponding problems of thermomechanics for shape memory alloys were considered in a geometrically linear formulation.
In [4], the issue of modeling pseudo-elastic-plastic bodies with deformations up to 6% using geometric nonlinearity was investigated.
Experimental results show that with increasing plastic deformation, the residual deformation increases and the phase deformation curves of the transformation stress from martensite to austenite become steeper and less obvious [2].
Analytical-numerical approach to describe the diagram of material during unloading starting from an arbitrary point of active site. The experimental results shown in Figure 2 were used as a basis. The curve was approximated in the corresponding section by means of a stressed spline [3].
Figure: 1. Schematic diagram of material for textured and non-textured alloy (with deformations up to 6%)
Figure: 2. Diagram of material for active release when unbound for textured and non-textured alloy (with deformations up to 14%)
Conclusions. The influence of large deformations (up to about 15%) arising from plastic deformation of martensite on the mechanical behavior of textured and non-textured alloy is studied in this work. A schematic diagram of the material before and after the phase transformation is constructed.
Similar problems were solved in a geometrically linear formulation with deformations up to 6%. Experimental results show that with increasing plastic deformation, the residual deformation increases and the phase strain curves of the conversion stress from martensite to austenite become steeper and less obvious.
The paper proposes an analytical-numerical approach to describe the diagram of the material during unloading starting from an arbitrary point of the active site. The experimental results shown in Figure 2 and the approximation of the curve in the corresponding section by means of a stressed spline were used as a basis [3].
References
1. Steblyanko P. Phenomenological Model of Pseudo-Elastic-Plastic Material Under Nonstationary Combining Loading/ P. Steblyanko, Y. Chernyakov, A. Petrov, V. Loboda // Structural Integrity, Volume 8, Theoretical, Applied and Experimental Mechanics, Springer Verlag, 2019.- P. 205-208.
2. Wang X.M. Micromechanical modelling of the effect of plastic deformation on the mechanical behaviour in pseudoelastic shape memory alloys. / X.M. Wang, B.X. Xu, Z.F. Yue // International Journal of Plasticity 24, 2008. - P. 1307-1332.
3. Стеблянко П.А. Мeтоды расщепления в пространственных задачах теории пластичности / П.А. Сгеблянко. - Киев: Наукова думка, 1998. -304с.
4. Petrov A. Development of the method with enhanced accuracy for solving problems from the theory of thermo-psevdoelastic-plasticity / А. Petrov, Yu. Chernyakov, P. Steblyanko, K. Demichev, V. Hay-durov // Eastern-European Journal of Enterprise Technologies. 2018. Vol. 4/7 (94). P. 25-33.
