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The effect of model size and boundary conditions on the representativeness of digital material representation simulations of ferritic-pearlitic sample compression

Perzyński Konrad

Computer Methods in Materials Science

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2022

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Vol. 22, No. 2

59--66

EN

The main objective of this work is to investigate the representativeness of the digital material representation (DMR) models of ferritic-pearlitic steel generated by the hybrid cellular automata (CA) / Monte Carlo (MC) algorithm. Particular attention is focused on determining the effect of the size of the digital representation model on its representativeness under deformation conditions simulated with the finite element (FE) framework. In addition, the effect of periodic and non-periodic boundary conditions on the deformation behaviour of DMR models is analysed. A dedicated buffer zone approach applied the periodic boundary conditions on non-periodic finite element models. The results of equivalent stresses and strains and their average values are used to evaluate the differences between the models’ predictions.

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Evaluation of capabilities of the nanoindentation test in the determination of flow stress characteristics of the matrix material in porous sinters

Madej Lukasz, Legwand Adam, Setty Mohan, Mojzeszko Mateusz, Perzyński Konrad, Roskosz Stanisław, Chrapoński Jacek

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 1

art. no. e21, 2022

EN

Herein, we evaluate the nanoindentation test capabilities in the determination of flow stress characteristics of the matrix material in porous sinters. The Distaloy AB sample with 15% porosity after the sintering operation is selected as a case study for the investigation. 2D and 3D imaging techniques are employed first to highlight difficulties in identifying reliable nano hardness measurement zones for further properties evaluation. Then, nanoindentation test results are acquired with Berkovich tip pressed under various loads at different locations in the sample. Systematic indentations in the quartz sample are used as a cleaning procedure to minimize the effect of the possible build-up around the indenter tip. The representative indentation load range is selected based on the extracted material characteristics. With that, the stress–strain response of the sinter matrix material is identified. The reliability of the determined flow stress curve is confirmed with the use of conical nanoindentation measurement results and finite element simulations. Obtained results show that it is possible to calculate reliable flow stress characteristics of the matrix in the porous samples, with the assumption that experiments under various loading conditions and from various locations in the matrix are performed. It is also pointed out that various indentation loads should be used to eliminate the influence of the pile-up or scale effects that affect the overall material response.

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Preface

Perzyński Konrad, Bzowski Krzysztof

Computer Methods in Materials Science

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2019

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Vol. 19, No. 2

40

EN

This special issue 2/2019 of the CMMS journal is dedicated to the carefully selected topics, which were presented during the ECCOMAS 5th Young Investigators Conference YIC 2019, held in Krakow, Poland, on September 1-6, 2019.