COMPUTER METHODS IN MATERIALS SCIENCE (CN-cmms)

Permanent URI for this communityhttps://repo.agh.edu.pl/handle/AGH/102744

Adres wydawniczy: Kraków : Akapit, 2006- . Od vol. 20, no. 3 (2020): Wydawnictwa AGH.
Strona WWW: https://www.cmms.agh.edu.pl/
ISSN: 2720-4081 eISSN: 2720-3948
(Poprzedni ISSN: 1641-8581)
DOI: https://doi.org/10.7494/cmms
Poprzedni tytuł: Informatyka w Technologii Materiałów (2001-2005)

Computer Methods in Materials Science povides an international medium for the publication of studies related to various aspects of applications of computer methods in the broad area of materials science.

New! Aktualny numer: 2025 - Vol. 25 - No. 4

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Computer Methods in Materials Science
2025 - Vol. 25 - No. 4
Access status: Open Access ,
Full-field approaches for austenite-ferrite phase transformation simulations
(Wydawnictwa AGH, 2025) Wermiński, Mariusz; Sitko, Mateusz; Madej, Łukasz
Understanding the local evolution of phase transformations in steels, particularly the γ (austenite) → α (ferrite) transformation, is crucial for controlling the microstructure and properties of steel components. Over recent decades, significant progress has been made in the numerical modeling of this complex phenomenon. This development has been driven by both scientific curiosity and industrial needs, especially in processes such as hot rolling, forging, thermal treatment, etc. The developed models have evolved from simple solutions based on local equilibrium to more complex approaches that consider local heterogeneities. Modern computational approaches, such as Phase-Field (PF), Level-Set (LS), Cellular Automata (CA), Monte Carlo (MC) or Vertex based simulations, allow for the precise reproduction of microstructural evolution considering local instabilities. They also enable the analysis of phase boundary motion in an explicit manner. These techniques also allow for direct integration with thermodynamic data and mechanical models, thereby better capturing the physical mechanisms of phase transformations, such as chemical composition, diffusion resistance, or the influence of deformation. An overview of the state of the art in this area is presented within the paper. The model’s concepts, assumptions, fundamental equations, advantages, limitations, and potential practical applications are summarized. Special attention is given to modeling the γ → α transformation by the Cellular Automata method. The importance of incorporating phenomena such as diffusion, nucleation, and growth is emphasized. The need for consistency between experimental results and simulations is also highlighted.
Access status: Open Access ,
High-fidelity modeling of interface crossing in the diffusion welding process at the polycrystalline scale
(Wydawnictwa AGH, 2025) Godinot, Camille; Rigal, Emmanuel; Bernard, Frédéric; Emonot, Philippe; Frayssines, Pierre-Eric; Védie, Luc; Bernacki, Marc
Controlling the microstructure of a diffusion welded interface is a critical point to ensure optimum mechanical properties and the homogeneity of the joint. Beyond the intimate contact formation between bonded parts studied in the literature, this article focuses on the grain boundary crossing of the interface during this process and its measurement. Following this perspective, a level-set method has been used for full-field microstructure simulations in 2D with various interface parameters. Two crossing measurement models have been formulated, tested and discussed over the simulations.
Access status: Open Access ,
Polycrystalline plasticity analysis of cyclic loading and stress relaxation in 316H austenitic stainless steel
(Wydawnictwa AGH, 2025) Acar, Sadik Sefa; Yalçinkaya, Tuncay
The mechanical behavior of 316H austenitic stainless steel is investigated in this study under cyclic strain-controlled loading with and without hold periods at elevated temperatures. Understanding the low-cycle fatigue (LCF) and fatigue-creep interaction (FCI) characteristics is essential for ensuring the structural performance and safety of reactor components, particularly under conditions typical of modular and generation IV reactors. The new generation of nuclear power plants require more resistant and durable materials as the operating environments impose significantly higher demands, including increased neutron irradiation levels and elevated operating temperatures, leading to accelerated material degradation. A combined isotropic-kinematic hardening model within a crystal plasticity framework is employed to capture the cyclic and time-dependent mechanical response of the material. Model parameters are calibrated by fitting cyclic loading simulation results to experimental data at 550°C using polycrystalline representative volume elements (RVE). Strain-controlled uniaxial loading simulations are performed to analyze peak stress evolution throughout cyclic loading and stress relaxation behavior during strain-hold periods. The RVE simulation results are in strong agreement with experiments under LCF loading. For the loading with strain-holds, stress relaxation during hold periods exhibits two distinct stages: an initial rapid decay followed by a steady decline, both of which are captured in simulations. Beyond the macroscopic response, analyses reveal the heterogeneous evolution of field variables at the microstructural level, as strain hardening during loading and stress relaxation during hold periods varied across grains due to their crystal orientations and interactions with neighboring grains. These findings enhance the understanding of high-temperature mechanical behavior at both macroscopic and microstructural scales, contributing to the efforts for the design, operation, and life extension of nuclear reactor components.
Computer Methods in Materials Science
2025 - Vol. 25 - No. 3
Access status: Open Access ,
An evaluation of discrepancies between CPFE simulations and mean-field approximations for dual phase materials
(Wydawnictwa AGH, 2025) Mirhosseini, Shahrzad; Atzema, Eisso H.; van den Boogaard, Antonius H.
This paper explores the discrepancies observed between 2D and 3D crystal plasticity finite element (CPFE) simulations and mean-field approximations in terms of macroscopic flow curves. Two hypotheses are proposed to address the discrepancies: (1) the type of yield function in the mean-field approach, and (2) differences in stress states between the two methodologies. Based on the first hypothesis, the type of yield function may influence the stress-strain partitioning in the mean-field approach. Consequently, the von Mises criterion is replaced with the Hershey yield function. To test the second hypothesis, CPFE simulations are extended to 3D to achieve comparable stress states in both methods. This analysis reveals that the exact shape of the yield function has a marginal impact on the discrepancies, whereas the proper 3D stress distribution significantly reduces them. This comprehensive study also uncovers a limitation of the mean-field approach in terms of accuracy in the prediction of macroscopic material response and stress partitioning for a two-phase polycrystalline material.
Access status: Open Access ,
Analysis of the decay time and bound-states energies of a particle in a specific structure GaMnAs/GaAs quantum well
(Wydawnictwa AGH, 2025) Ali, Alaa Y.; Ali, Hassan H.; Ali, Mustafa Y.
The bound states and decay time in a certain quantum well structure (GaMnAs/GaAs) were analysed and identified at the minimum decay time. Through the analysis of quantum mathematical equations, we derived specific formulas for energies that significantly amplify the numerical solutions of equations throughout all dimensions of confinement. Without altering the parameters utilized, the quantification, barriers, and well width were predominantly influenced by the spatial dimension parameters, such as the barrier height and well width. The principal bound state and lowest decay time were determined at a well width of 40 Å and a barrier thickness of 46.27 Å. This work revealed a novel characteristic known as interfacial tunnelling, which refers to the phenomenon where an electron establishes a tunnelling state between two interfaces. This tunnelling process is significantly influenced by the characteristics of the materials used, as well as the dimensions of the wells and barriers.
Access status: Open Access ,
Design and implementation of a digital infrastructure for autonomous open-die forging
(Wydawnictwa AGH, 2025) Rechenberg, Roy; Korpala, Grzegorz; Jabłońska, Magdalena; Wojtaszek, Marek; Zyguła, Krystian; Tkocz, Marek; Bednarczyk, Iwona; Kowalczyk, Karolina; Prahl, Ulrich
Open-die forging is a key process for manufacturing large components such as generator shafts and crankshafts for ship engines. Despite its industrial relevance, the process remains dependent on manual labour and operator expertise, leading to challenges in process stability, reproducibility, and efficiency. Traditional automation approaches are impractical due to the high variability and low production volumes typical of open-die forging. At the Institute of Metal Forming (IMF) at the TU Bergakademie Freiberg, a novel concept for autonomous open-die forging has been developed and tested. The system combines conventional forging equipment with advanced technologies, including industrial robotics, 3D laser scanning, thermal imaging, and modular control software. Central to the concept is a robot cell operating as a distributed system, where sensor data is used to create a digital twin of the workpiece. This enables adaptive process planning and real-time autonomous operative adjustments. A process planning tool generates pass sequences and commands for manipulator movements, while an electromechanical interface allows indirect control of the forging press. The modular software architecture, coordinated by a central core-module, ensures flexibility and facilitates integration into different production environments. Initial trials demonstrate the system’s potential to improve process stability and quality while reducing dependency on manual operation. Ongoing work focuses on refining the concept to meet industrial requirements and support advanced material applications.
Access status: Open Access ,
The application of numerical simulations to analyze the forward extrusion process along with the verification of results and tuning of the numerical model
(Wydawnictwa AGH, 2025) Hawryluk, Marek; Dudkiewicz, Łukasz; Marzec, Jan; Tkocz, Roger; Borowski, Jacek; Ficak, Grzegorz; Jóźwiak, Bartosz; Ziemba, Jacek
The paper presents the application of numerical simulations based on the Finite Element Method (FEM) for analyzing and optimizing the extrusion processes of aluminum and lead. These processes are efficient methods for manufacturing critical machine parts and metal components, ensuring excellent mechanical properties. A detailed analysis was conducted on the numerical modeling of the impact of die taper angles on strain distribution and forming forces during co-extrusion. The study found that a 45-degree angle provides optimal deformation conditions, minimizing extrusion forces and reducing the formation of dead zones compared to a 90-degree angle. Numerical simulations, supplemented by technological trials under semi-industrial conditions and image analysis involving the deformation of the coordinate grid, provided key insights into a material flow, strain distribution, and force parameters. The results emphasize the importance of validating numerical models with semi-industrial experiments to ensure accuracy and reliability, as assuming constant tribological conditions may not reflect actual process conditions, including the formation of dead zones for angles greater than 45°. It was only through a thorough analysis of the actual process and the introduction of variable friction coefficients for individual tools that a dead zone was achieved in the modelling. The findings from this research can serve as the foundation for further optimization and adaptation of technological processes, aiming to further enhance extrusion processes through the use of numerical simulations.
Computer Methods in Materials Science
2025 - Vol. 25 - No. 2

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