A computationally fast and accurate procedure for the identification of the Chaboche isotropic-kinematic hardening model parameters based on strain-controlled cycles and asymptotic ratcheting rate

The Chaboche isotropic-kinematic hardening (CIKH) model provides a versatile and realistic description of the material stress–strain behavior under generic multiaxial cyclic loadings. However, identifying the backstress parameters is challenging, and can be formulated as an optimization problem usin...

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Bibliographic Details
Published in:International journal of plasticity Vol. 160; p. 103503
Main Authors: Santus, C., Grossi, T., Romanelli, L., Pedranz, M., Benedetti, M.
Format: Journal Article
Language:English
Published: Elsevier Ltd 01.01.2023
Subjects:
Constitutive behavior
Elastic–plastic material
Mechanical testing
Numerical algorithms
Stress relaxation
Stress relaxation
Constitutive behavior
Mechanical testing
Elastic–plastic material
Numerical algorithms
ISSN:0749-6419, 1879-2154
Online Access:Get full text
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Summary:The Chaboche isotropic-kinematic hardening (CIKH) model provides a versatile and realistic description of the material stress–strain behavior under generic multiaxial cyclic loadings. However, identifying the backstress parameters is challenging, and can be formulated as an optimization problem using different approaches. Instead of a computationally expensive pointwise search, in this paper the global properties of the cyclic curves are fitted to the experimental data. The conditions introduced are the hysteresis areas, peak stress values and tangent moduli at the extreme points, however the framework can be easily adapted to other target quantities. One linear and two non-linear backstress components of the kinematic hardening model are introduced, although the analytical equations developed can be used to refine the model further, with more components. Two stabilized cycles are required to identify the main kinematic parameters. New analytical expressions for asymptotic ratcheting rates in uniaxial tests are developed and then used to tune the dynamics of the slightly non-linear (hence, slowest) backstress component. After obtaining the kinematic parameters, isotropic hardening laws can also be identified, by considering the evolution of the extreme points of the strain-controlled cycles before stabilization. Practical demonstrations of the procedure are provided by experimental tests carried out on a 7075-T6 aluminum alloy, 42CrMo4+QT steel, and a high-silicon ferritic ductile cast iron. An accurate reproduction of the material behavior is achieved, at a negligible computational cost. [Display omitted] •A procedure is proposed for identifying Chaboche model parameters.•The main global properties of the stabilized cycles and the ratcheting are imposed.•The isotropic component parameters are easily found after the kinematic ones.•Analytical expressions for the asymptotic ratcheting rate are found and implemented.•Applications of the procedure on different metals are provided with validations.
ISSN:0749-6419
1879-2154
DOI:10.1016/j.ijplas.2022.103503