Engineering Mechanics

Proceedings Vol. 27/28 (2022)

ENGINEERING MECHANICS 2022

Copyright © 2022 Institute of Theoretical and Applied Mechanics of the Czech Academy of Sciences, Prague

 

Klepač V., Parma S., Svárovský J., Marek R., Plešek J.
pages 197 - 200, full text

Ratcheting still remains as a critical process for simulations. To capture material behavior, there is a vast of models of plasticity, from which we select rules of kinematic hardening (KH). To present whole workflow of ratcheting predicition, the model of Multicomponent Armstrong Frederick with Threshold with r modification (MAFTr) was selected. This model is based on concept of multicomponent backstress and was presented by Dafalias and Feigenbaum in 2010. We implemented the MAFTr model into commercial FE code Abaqus Standart via the UMAT interface. Implementation was verified by comparision of backstress components evolution in FE implementation and closed form solution derived for the case of uniaxial loading. To demonstrate the performance of UMAT subroutines, numerical examples and their computational demands will be shown. Even the well designed model is strongly influenced by identification of parameters. As the initial estimation, parameters will be found on the case of uniaxial monotonic loading using the closed form solution. For the case of calibration on more complex problems, the use of FE solution is required, so the computational demands are. Hence, effective computational approaches must be employed. The approach to calibration procedure will also be presented.

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