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.

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Computer Methods in Materials Science
2021 - Vol. 21 - No 2
Access status: Open Access ,
Multiobjective optimiaztion of microstructure parameters in a thermoelastic porous material by means of differential evolution and elements of game theory
(Wydawnictwa AGH, 2022) Długosz, Adam; Schlieter, Tomasz
The paper is devoted to the optimization of the microstructure parameters of a porous medium under thermo-mechanical loading. Four different criteria related to the properties of the porous material have been proposed and numerically implemented. To solve a multiobjective problem, a novel method based on the coupling of differential evolution and elements of game theory is used. The proposed algorithm features an appropriate balance between exploration and exploitation of objective space, which is necessary for the successful optimization of these types of tasks with the use of numerical simulations. The model of the thermo-elastic porous material is composed of two-scale direct analysis based on a numerical homogenization. Direct thermoelastic analysis with representative volume element (RVE) and finite element method (FEM) is performed. Numerical example of the optimization illustrating the usefulness of the proposed method is included.
Access status: Open Access ,
Artificial intelligence approach for detecting material deterioration in hybrid building constructions
(Wydawnictwa AGH, 2021) Česnokov, Andrej Vladimirovič; Mihajlov, Vitalij Vital?evič; Dolmatov, Ivan Viktorovič
Hybrid constructions include heterogeneous materials with different behaviors under load. The aim is to achieve a so-called synergistic effect when the advantages of particular structural elements complement each other in a unified system. The building constructions considered in the research include high-strength steel cables, fiberglass rods, and flexible polymer membranes. The membrane is attached to the rods which have been elastically bent from the initially straight shape into an arch-like form. Structural materials inevitably deteriorate during a long operational period. The present study focuses on detecting material deterioration using Artificial Neural Networks (ANNs), which belong to the scope of intelligent techniques for data analysis. Appropriate ANN structures and required features are proposed. A semi-supervised learning strategy is used. The approach allows the training of the networks with normal data only derived from the construction without defects. Material degradationis detected by the level of reconstruction error produced by the network given the input data. The work contributes to the field of structural health monitoring of hybrid building constructions. It provides the opportunity to detect material deterioration given the forces in particular structural elements.
Computer Methods in Materials Science
2021 - Vol. 21 - No 3
Computer Methods in Materials Science
Vol. 22 (2022)
Computer Methods in Materials Science
2025 - Vol. 25 - No. 4
Access status: Open Access ,
Investigation of the suitability of a fused filament fabricated tool for incremental sheet metal forming
(Wydawnictwa AGH, 2023) Weise, Dieter; Langner, Christian; Pierer, Alexander; Kraeusel, Verena; Petru, Jana; Koziorek, Jiri; Prauzek, Michal
Incremental sheet forming (ISF) is a flexible manufacturing process for sheet metal parts in small to medium quantities. Successive movements of a stylus create the geometry of the sheet metal part. ISF can be performed with or without a counter tool. By using counter tools, the geometry deviation of the formed sheet metal part can be reduced. To achieve the broader application of ISF, counter tools must be cost-effective, fast, and individually producible, even for batch sizes of only one part. In addition to milling, which has been the main method used to date, additive manufacturing (AM) also makes it possible to meet these requirements for flexible counter tool production. To investigate the suitability of AM for the production of counter tools for the ISF and to learn more about the load on the counter tool, a cylindrical counter tool made of polylactic acid (PLA) was produced using the fused filament fabrication (FFF) process. This counter tool was used for the ISF of drawing steel. Based on the force measurement results, a first step towards suitability evaluation of 3D-printed counter tools for ISF was taken, and possibilities, as well as application limits for such counter tools were discussed.
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.
Access status: Open Access ,
Considering semi-crystallinity in molecular simulations of mechanical polymer properties - using nanoindentation of polyethylene as an example
(Wydawnictwa AGH, 2021) Fritz, Susanne
Molecular dynamic (MD) simulations have been used to investigate the response of semi-crystalline polymers in nanoindentation tests, using polyethylene (PE) as an example. To that purpose, semi-crystalline simulation boxes of linear PE with various chain lengths up to C2000 were created by homogeneous nucleation during the non-isothermal cooling of melts. The final crystallinity depended on the chain length and the cooling rate used and could be estimated using various parameters like density, fraction of bonds in trans conformation, and energy terms. The simulation boxes were transferred into surface models and subjected to nanoindentation tests using non equilibrium MD. This allowed the deformation behaviour of the material to be analysed directly. Strong dependencies on the crystallinity of the PE were found, which underlines the importance of considering crystallinity when investigating the mechanical properties of semi-crystalline polymers by means of simulations.
Access status: Open Access ,
On the prognosis of the growth of a heterostructure from a gas phase to analyze the possibility of decreasing mismatch-induced stresses
(Wydawnictwa AGH, 2021) Pankratov, Evgenij Leonidovič
An approach to decreasing mismatch-induced stress in a heterostructure by radiation processing during growth from the gas phase is introduced in this paper. Within the framework of the approach with decreasing mismatch-induced stresses, one can find the acceleration of the recombination and diffusion of radiation defects generated during radiation processing. An analytical approach for analyzing mass and heat transfer is also introduced. The approach provides the opportunity to simultaneously take into account spatial and temporal variations of mass transfer parameters. At the same time, the approach allows the nonlinearity of the considered processes to be taken into account.
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 ,
Application of the design of experiments and statistical hypothesis to reduce defects in the flange of the steel plate process
(Wydawnictwa AGH, 2022) Sadłowska, Hanna; Wójcik, Piotr
The paper presents a discussion on the occurrence of defects in the circumferential flange of steel plate. The numerous flange face defects have been analysed. The types of defects have been selected and categorized using an experimental planning procedure involving 600 samples for 24 different process variants, considering variables such as material, hole diameter, tool size and tool position. The analysis of experimental results enabled to determine of the optimal values of process parameters to minimize the occurrence of defects. Furthermore, the influence of individual parameters on the quality of the flange surface has been carried out to obtain the process parameters' impact using statistical hypotheses. As a result, it was possible to develop rules which will be helpful in the design process, especially important when changing the material to be processed.
Access status: Open Access ,
Computer modelling of the ablation casting process and prediction of the strength properties of AC-42000 castings
(Wydawnictwa AGH, 2022) Małysza, Marcin; Puzio, Sabina; Major-Gabryś, Katarzyna; Głowacki, Mirosław; Wilk-Kołodziejczyk, Dorota; Kamińska, Jadwiga
The demand for castings with superior properties has compelled the development and optimization of manufacturing technologies. By further developing already known techniques, we are able to contribute to the introduction of new research possibilities. The article presents the methodology of conducting simulation tests of the gravity casting process into sand moulds with the use of ablation. The ablation technique consists in spraying water through evenly spaced nozzles onto a mould into which the liquid casting alloy has been poured. The conducted research focuses on an alloy from the group of Al-Si alloys. In order to compare the effects of different techniques, additional tests were carried out for gravity casting into sand and metal die moulds. At the same time, virtual experiments were conducted to develop a simulation methodology for ablation casting technology, taking into account mould degradation. Additionally, the possibility of predicting the final mechanical properties of various manufacturing technologies was tested. Destructive tests were carried out to determine the mechanical properties in the cast samples, as well as microstructure tests and secondary dendrite spacing. The results of the mechanical tests are compared with the predicted simulation properties.
Access status: Open Access ,
Shear strength estimation of a FRP-strengthened RC beam: A comparison between an artificial neural network and guideline equations
(Wydawnictwa AGH, 2024) Nezaminia, Hamid
In recent years, several experimental tests have been conducted on the shear strengthening of reinforced concrete (RC) beams strengthened by fiber-reinforced polymer (FRP) systems. In this regard, some equations have also been proposed to estimate the shear strength of beams reinforced with FRP systems. The aim of this study is to investigate the estimation of the shear strength of beams reinforced with FRP systems using an artificial neural network model. For this purpose, a comprehensive and extensive review of forty published articles has been carried out to compile data on 304 RC beams strengthened with externally bonded FRP systems to improve their shear strength. These laboratory results have been used to provide a database for the ANN model to evaluate the shear behavior. The input to the ANN model consists of the 11 variables, including the sectional geometry, reinforcement ratio, FRP ratio, and the characteristics of concrete, steel reinforcement, and composite material, while the output variable is the shear strength of the FRP-strengthened RC beam. In order to evaluate the effectiveness of the neural network model in estimating the shear capacity of RC beams, the results obtained from the neural network model are compared with the equations from the Publication No. 345 and ACI 440.2R guidelines. The comparison of the results shows that the predictive power of the proposed model is much better than the experimental guidelines. Specifically, the mean absolute relative error (MARE) criteria for the studied data is 13%, 34% and 39% for the ANN model, ACI 440.2R guideline and the Publication No. 345 guideline, respectively.
Computer Methods in Materials Science
2022 - Vol. 22 - No 1
Access status: Open Access ,
A new BEM for modeling and simulation of 3T MDD laser-generated ultrasound stress waves in FGA smart materials
(Wydawnictwa AGH, 2021) Fahmy, Mohamed Abdelsabour
The goal of this study is to present a new theory known as the three-temperature memory-dependent derivative (MDD) of ultrasound stress waves in functionally graded anisotropic (FGA) smart materials. It is extremely difficult to address the difficulties related to this theory analytically due to its severe nonlinearity. As a result, we suggest a new boundary element method (BEM) to solve such equations. The suggested BEM technique incorporates the benefits of both continuous and discrete descriptions. The numerical results are visually represented to demonstrate the impacts of MDD three temperatures and anisotropy on the ultrasound stress waves in FGA smart materials. The numerical findings verify the proposed methodology's validity and accuracy. We may conclude that the offered results are useful for comprehending the FGA smart materials. As a result, our findings contribute to the advancement of the industrial applications of FGA smart materials.
Access status: Open Access ,
Identification of the average and local boundary condition of heat transfer during cooling with a water spray under surface boiling
(Wydawnictwa AGH, 2020) Jasiewicz, Elżbieta; Hadała, Beata; Malinowski, Zbigniew
The study determined the local and average heat transfer coefficient and the heat flux on the surface of a cylinder cooled with a water nozzle. The inverse method was used to identify the heat transfer coefficient. An objective function was defined to determine the distance between the measured and calculated temperatures. Two models describing the heat transfer coefficient on the cooled surface were considered. The first model described changes in the heat transfer coefficient as a function of the sample radius and cooling time, and the second one assumed the dependence of the heat transfer coefficient solely on time. Numerical simulations showed significant differences in the determined heat transfer coefficients depending on the adopted model of the boundary condition. The performed tests included experimental temperature measurements at selected points of the sensor, numerical simulations of temperature changes, and the inverse solution.
Access status: Open Access ,
Viscoelastic characterization of additively manufactured acrylonitrile butadiene styrene
(Wydawnictwa AGH, 2023) Witek, Szczepan
The main objective of this work was to characterize the viscoelastic properties of additively manufactured Acrylonitrile Butadiene Styrene based on tensile stress relaxation tests. The stress relaxation measurements were conducted with a temperature range of 25-100°C. The two-layer viscoplastic constitutive model was adopted to describe the elastic and viscous behavior of the investigated material. The model parameters were calibrated using an inverse analysis and stress relaxation data. The model's predictive capabilities were assessed by comparing the model predictions with experimental data not included in the calibration process.
Access status: Open Access ,
The influence of material aging on the structural behavior of a flexible roof with a polymer membrane shell
(Wydawnictwa AGH, 2021) Česnokov, Andrej Vladimirovič; Mihajlov, Vitalij Vital?evič; Dolmatov, Ivan Viktorovič
The roof structure considered in the research consists of continuous cables and a number of spreaders forming a three-dimensional frame. The frame is covered with a polymer membrane made of flexible architectural fabrics. The elements of the roof are compact and suitable for transportation to remote construction sites. The roof also has advantages for developing areas with harsh climatic conditions. The flexible elements of the roof, however, only provide transmission of tensile forces. Under compression, cables slacken and the membrane becomes wrinkled. Pre-tension of the flexible elements, which is introduced to retain the operability of the roof, tends to gradually diminish due to material aging. The aging results in the alteration of strength properties and creep elongation of the structural elements. It induces membrane tearing on local areas. Force alteration in primary structural members is examined in the present study, with statistical methods used for data analysis. They include significance hypothesis testing and correlation coefficients estimation. The data are obtained by the Finite Element simulation of the roof using EASY-2020 software. The results of the work may be used for life expectancy assessment of flexible roof structures, providing important information for the preliminary design stage. The work contributes to the safety enhancement of cable-membrane structures and the expansion of their scope in permanent building constructions.
Access status: Open Access ,
Capabilities of numerical simulation support for defect investigations in die forgings
(Wydawnictwa AGH, 2024) Hawryluk, Marek; Polak, Sławomir; Dudkiewicz, Łukasz; Marzec, Jan; Jabłońska, Magdalena; Suliga, Maciej; Tkocz, Roger; Korpala, Grzegorz
The article concerns the use of the results of numerical simulations, primarily for the detection of defects in forged products identified at various stages, along with the analysis of the geometry of forgings and the way in which the material flows in tools. The work presents the results of measurements and analyses using numerical modelling based on computational packages dedicated to forging processes such as: QForm, Forge, etc., which are equipped with special functions that significantly facilitate analyses by both technicians and designers. These functions include: contact of the deformed material with the tool, flow line distribution, “trap” or “fold” functions for detecting forging defects, as well as other technological parameters and physical sizes, which are crucial in the case of a comprehensive analysis of the industrial die forging process. The novelty of the work is the presentation of the possibility of simultaneously combining many different non-destructive techniques and methods, e.g. results of FE simulations with 3D reverse scanning, minimizing interference in the industrial process. The research carried out allows for the thorough and rapid analysis of the correctness of the deformation of the forging material for selected forging processes, along with the presentation of methods for their prevention and solving va