Browsing by Subject "finite element method"

Now showing 1 - 20 of 41

Access status: Open Access ,
Advanced Method for Determining Land Plot’s Physical Surface
(Wydawnictwa AGH, 2024) Malashevskyi, Mykola; Malashevska, Olena
"This study examines the issue of the accuracy of physical surface calculations for land plots with complex configurations and reliefs. The goal of the study was to develop a methodology for determining the surface area of land plots with complex configurations and reliefs. The presented model was based on the finite element method. The developed method allows one to evaluate a relief’s complexity by using a dimensionless mean physical surface complexity factor"," a Fortran program was developed for the methodology. Experiments that proved the effectiveness of the methodology and a comparative analysis of those areas that were calculated by the presented method and TIN model were carried out. The research findings proved the practicability of the methodology for calculating the physical surfaces of land plots with complex configurations. The presented methodology can be used for flood modeling, landscape and vertical planning, etc."
Access status: Open Access ,
Analiza numeryczna skuteczności zastosowania wstecznych otworów w świdrach udarowo-obrotowych
(2007) Knez, Dariusz; Bednarz, Stanisław
The percussion-rotary bits used for drilling blast holes in mining is still justifiable from the economical point of view. Cogged-bits are more frequently applied than the cross-blade bits. The drilling rate and footage are to some extent limited by the quality of washing the wellbore bottom. The disturbed process of cuttings removal from the well with air mud in the zone where the bit is connected with the downhole hammer. Attempts at using the reverse holes in the bit body were made. The analytical description of the effect is hindered by the complex shape of the space in which the mud is flowing. Therefore, the use of numerical methods enables detailed description of drilling mud flow in view of the analyzed problem. The paper presents the results of computer simulations in the form of maps of pressure and flow rate in the zone of the bit and downhole hammer.
Access status: Open Access ,
Analiza wytrzymałościowa MES spągnicy obudowy zmechanizowanej »Glinik 15/32 Poz«
(2006) Badura, Sławomir; Bańdo, Dariusz; Migacz, Katarzyna
The paper presents strength analysis of uniform roof supports for caving »Glinik 15/32 Poz« working in an underground coal mine using the finie element analysis method. This analysis uses the professional FEM package NE/Nastran for a Microsoft Windows based system. The paper highlights three different case studies of base roof supports for caving using simulations of different working modes.
Access status: Open Access ,
Applications of alternating direction solver for simulations of time-dependent problems
(Wydawnictwa AGH, 2017) Łoś, Marcin Mateusz; Paszyński, Maciej
This paper deals with the application of an Alternating Direction Solver (ADS) to a non-stationary linear elasticity problem solved with the isogeometric finite element method (IGA-FEM). Employing a tensor product $B$-spline basis in isogeometric analysis under some restrictions leads to a system of linear equations with a matrix possessing a tensor product structure. The ADI algorithm is a direct method that exploits this Kronecker product structure to solve the system in $O (N)$, where $N$ is the number of degrees of freedom (basis functions). This is asymptotically faster than state-of-the-art, general-purpose, multi-frontal direct solvers when applied to explicit dynamics. In this paper, we also present a complexity analysis of the ADS incorporating dependence on the $B$-spline basis of order $p$.
Access status: Open Access ,
Artificial intelligence-enhanced algebraic multigrid for 3D finite element simulations
(Wydawnictwa AGH, 2026) Goik, Damian; Banaś, Krzysztof
The paper presents preliminary investigations into a strategy for solving linear systems resulting from 3D finite element simulations, based on the algebraic multigrid (AMG) method, enhanced using artificial intelligence techniques. In particular, we adapt to 3D problems the algorithm presented in Luz et al. (2020) for using a graph neural network to create the prolongation and restriction operators in a way that will improve convergence. The process of training the network proceeds on the basis of a set of system matrices obtainedfor tasks much smaller in scale than the target problem to be solved. Learning is aimed at decreasing the spectral radius of the error propagation matrix after applying modified prolongation and restriction. We describe some implementation details of the solver developed based on the presented strategy and show several numerical examples of its application for medium-sized problems.
Access status: Metadata only ,
Classical and isogeometric finite element method
(Akademia Górniczo-Hutnicza im. St. Staszica w Krakowie, 2021) Paszyński, Maciej; Paszyński, Maciej
Wydział Informatyki, Elektroniki i Telekomunikacji; Centrum e-Learningu i Innowacyjnej Dydaktyki
The textbook presents a comprehensive introduction to the finite element method, including methods of isogeometric analysis. The chapters are supplemented with sample MATLAB codes (runnable in the free version of Octave). The textbook is aimed at students of engineering and computer science, and therefore focuses on the practical and implementation aspects of particular topics related to the finite element method.
Access status: Open Access ,
Computational modelling of localized deformations with regularized continuum models
(2011) Pamin, Jerzy
The paper presents a short overview of selected problems related to the numerical analysis of localized deformations. After defining the localization phenomenon and the class of gradient models, two simulation examples are shown. They are applications of the plasticity theory with a Laplacian of the hardening parameter and of the damage theory with an additional averaging equation for an equivalent strain measure.
Access status: Open Access ,
Computer modelling of microstructure development during multistage deformation
(2006) Nowak, Jarosław; Rauch, Łukasz
The objective of this paper is implementation of microstructure development equations and their inclusion in commercial finite element code of Forge2 software. The created module is used for prediction of microstructure evolution in hot metal forming process. Calculations were carried out based on multistage forging process. Inclusion of the structural model into the Finite Element Method (FEM) source codes creates possibilities to take into account microstructural features already at the designing stage of the final industrial process.
Access status: Open Access ,
Design of manufacturing of welding neck type rings
(2005) Malinowski, Zbigniew; Madej, Wiesław; Musiał, Andrzej; Hajduk, Zbigniew; Wolski, Aleksander
Computer aided design of the rolling process for welding neck 20' and 24' type rings on the Thyssen-Wagner 125-100 mill is described in the paper. Numerical simulations of processes of preform shaping and ring rolling were performed using ring-roll finite element software. The optimal shape of the preform and rolling curve were selected on the basis of results of simulations, as well as on the basis of experimental data. Values of stresses, strains, strain rates and temperatures during rolling were determined and resutts were validated by comparison with the data monitored during the real industrial process. Obtained results were used for the design of tools for forging and rolling of welding neck type rings.
Access status: Restricted ,
Dobór kształtu widelca roweru wyczynowego z wykorzystaniem MES
(Data obrony: 2017-01-27) Stępień, Marcel
Wydział Inżynierii Mechanicznej i Robotyki
Access status: Open Access ,
Effects of asymmetric rolling with tilted material entry on texture and mechanical properties of aluminium
Byrska-Wójcik, Dorota Joanna; Ostachowska, Monika; Gibek, Julia; Wierzbanowski, Krzysztof; Wróbel, Mirosław; Błoniarz, Remigiusz; Baczmański, Andrzej; Kopyściański, Mateusz; Kalemba-Rec, Izabela
Wydział Inżynierii Metali i Informatyki Przemysłowej; Wydział Fizyki i Informatyki Stosowanej; Wydział Fizyki i Informatyki Stosowanej
Asymmetric rolling texture of aluminium alloy 1050 was examined both experimentally and numerically. The rolling asymmetry was realized using rolls with different diameters rotating with the same angular velocity and by varying inclination of the rolling strip (i.e., the flat and tilted entry of the rolled strip between rolls). The final, 84% reduction in the thickness was obtained after six consecutive rolling passes. Crystallographic texture variation over the rolled bar thickness was determined using X-ray diffraction and predicted using the Finite Element Method combined with two crystalline deformation models (i.e., the elasto-plastic and the elasto-viscoplastic ones). Textures predicted by both models, taking into account all deformation process parameters, are in good agreement with experimental results. The obtained results confirm the effect of texture modifications caused by the shear stress component, resulting in the shifts of selected texture maxima in the orientation space, and explain the observed texture distribution across the sample depth. The novelty of this work consist in examination of the role of the tilted material entry (besides a difference in rolls diameters) in homogenization of texture distribution in multi-pass asymmetric rolling. The rolling geometry process variants, recommended for the technological practice, are indicated.
Access status: Open Access ,
Efficient simulations of large-scale convective heat transfer problems
(Wydawnictwa AGH, 2021) Goik, Damian; Banaś, Krzysztof; Bielański, Jan Gustaw; Chłoń, Kazimierz
We describe an approach for efficient solution of large-scale convective heat transfer problems that are formulated as coupled unsteady heat conduction and incompressible fluid-flow equations. The original problem is discretized over time using classical implicit methods, while stabilized finite elements are used for space discretization. The algorithm employed for the discretization of the fluid-flow problem uses Picard’s iterations to solve the arising nonlinear equations. Both problems (the heat transfer and Navier–Stokes equations) give rise to large sparse systems of linear equations. The systems are solved by using an iterative GMRES solver with suitable preconditioning. For the incompressible flow equations, we employ a special preconditioner that is based on an algebraic multigrid (AMG) technique. This paper presents algorithmic and implementation details of the solution procedure, which is suitably tuned – especially for ill-conditioned systems that arise from discretizations of incompressible Navier–Stokes equations. We describe a parallel implementation of the solver using MPI and elements from the PETSC library. The scalability of the solver is favorably compared with other methods, such as direct solvers and the standard GMRES method with ILU preconditioning.
Access status: Open Access ,
Elastic properties of composites reinforced by wavy carbon nanotubes
(2011) Górski, Radosław
In the paper the prediction of the elastic Young modulus of single-walled carbon nanotubes (CNTs) and the elastic properties of composites reinforced by straight or wavy CNTs is presented. The properties are evaluated by numerical methods. Nanotubes are modeled and analyzed by the finite element method (FEM). The specific atomistic nature of CNTs is taken into account by using a linkage between molecular and continuum mechanics. The methodology consists in replacing the discrete molecular structure of a CNT with a space-frame FE model by equating the molecular potential energy and the elastic strain energy of both models subjected to small elastic deformations. A three-dimensional frame is further substituted with a one-dimensional beam which represents the reinforcement in a representative volume element (RVE) of the considered composite. The properties of the nano-composite are determined by modeling and analyzing RVEs using the coupled boundary and finite element method (BEM/FEM). A two-dimensional matrix is modeled by the BEM and CNTs by the FEM using beam elements. The waviness and shape of a single fiber or multiple aligned nanotubes on the properties of the nanocomposite are investigated. Sinusoidal or arbitrary shapes of the reinforcement are considered. The influence of volume fraction of the reinforcement and the fiber/matrix Young's modulus ratio on the elastic properties of the composite is also studied.
Access status: Open Access ,
Enhancing mesh adaptation capabilities of GetFEM++ “FEM engine” with MAdLib library
(2013) Perduta, Anna
This paper describes enhancing mesh adaptation capabilities of GetFEM++ library. GetFEM++ is a versetile software package in C++ for implementing FEM based solvers for partial differential equations. Although GetFEM++ offers a wide range of mathematic tools for model descripion and discretization, it does only provide basic mesh refinement facilities. To enhance GetFEM++ capabilities, a mesh adaptation package MAdLib is used. The paper discusses basic requirements for mesh adaptation packages and presents MAdLib basic usage. The paper discusses implementation issues related to integration of both libraries. Examples illustrate capabilities of mesh adapation package and FEM framework extended by mesh adaptation facilities.
Access status: Open Access ,
Finite-element analysis of the tubing thread
(2006) Kopey, Bohdan; Kopey, Vladymyr; Bednarz, Stanisław; Savula, Stepan
Cycles of underground gas storage filling and unfilling imply axial loading and internal pressure to tubing thread with dynamic loading in the dangerous planes. The stress - deformation state of coupling with three levels of axial elongation resulted of screwing and external tension loading is presented. The amplitude - frequency descriptions of coupling and tubing screwed together are reached by the harmonic analysis of contact pressure vibrations. The action of vibrations can result in big reduction of contact stresses in tubing coupling thread connection. The computer finite-element axissymmetrical model of the tubing couplings has been developed. The first proper charge frequency is the most dangerous from point of view fatigue destruction of coupling in the critical plane of coupling (the first working pitch thread of pin and the last working pitch thread of box). The most dangerous frequencies of such coupling are the first and third proper charge frequency. Screwing together coupling results in smoothing amplitudes of contact pressure on the working sides of threads.
Access status: Open Access ,
Functionally graded porous material and its application in sandwich beams for bending and vibration behaviors
(Wydawnictwa AGH, 2024) Ton That, Lan Hoang
The article describes a functionally graded porous material in an application for sandwich beams. The bending and vibration behaviors of this structure are studied using the finite element method based on a simple beam model. The influences of some parameters, e.g., the porosity factor or the exponent graded, are also studied in this article. Finally, the numerical results are presented with some discussion.
Access status: Open Access ,
Gradient damage with volumetric-deviatoric decomposition and one strain measure
(2011) Wosatko, Adam
The paper presents a two-field formulation of the gradient-enhanced damage model and its application. This isotropic model is characterized by two damage parameters with a volumetric-deviatoric decomposition. However, one strain measure governs the development of damage as for the scalar description. The theory is verified by means of one-element benchmarks and also a more sophisticated simulation, namely the splitting of concrete cylinder in the Brazilian test is discussed.
Access status: Restricted ,
Jednorodne zagadnienie brzegowe dla dyfuzji wzajemnej w jednowymiarowej $r$-składnikowej mieszaninie
(Data obrony: 2012-10-19) Nowak, Robert
Wydział Matematyki Stosowanej
Access status: Restricted ,
Koncepcja kolektora dolotowego umożliwiającego wykorzystanie zjawisk dynamicznych
(Data obrony: 2017-07-06) Matusik, Krzysztof
Wydział Inżynierii Mechanicznej i Robotyki
Access status: Open Access ,
Mean field and full field modelling of microstructure evolution and phase transformations during hot forming and cooling of low carbon steels
(2020) Szeliga, Danuta; Bzowski, Krzysztof; Rauch, Łukasz; Kuziak, Roman; Pietrzyk, Maciej
The paper describes a critical comparison of mean field and full field approaches to modelling hot deformation/controlled cooling sequences for steels. Classification of the models, based on the balance between predictive capabilities and computing costs, is presented. Mean field models, which describe microstructure evolution and phase transformations were connected with thermomechanical finite element program and applied to simulation of the hot strip rolling process and cooling of tubes after hot rolling. Full field model described in the paper is a connection of the finite element (FE) and level set (LSM) methods. These methods were used to simulate heating/cooling sequence in the continuous annealing line. A suggestion to use a stochastic model as a bridge between mean field and full field approaches is made.