Národní úložiště šedé literatury Nalezeno 49 záznamů.  začátekpředchozí25 - 34dalšíkonec  přejít na záznam: Hledání trvalo 0.01 vteřin. 
Interní vnitropodniková metodika pro optimální dimenzování a využití šroubových spojů
Pařík, Petr ; Kolman, Radek ; Gabriel, Dušan
Zpráva popisuje interní vnitropodnikovou metodiku pro optimální dimenzování šroubových spojů podle normy VDI 2230.
Isogeometrický kontaktní analýza: studie explicitního dynamického kontaktního algoritmu
Kopačka, Ján ; Gabriel, Dušan ; Kolman, Radek ; Plešek, Jiří
V této práci byla navržena isogeometrická varianta explicitního konečnoprvkového kontaktního algoritmu, který zachovává symetrii kontaktních hranic. Upravený algoritmus byl testován na numerickém příkladu 2d dynamické Hertzovy úlohy rázu dvou válců bez tření. Pozornost byla věnována vlivu různých metod diagonalizace matice hmotnosti na oscilace kontaktní síly a kontaktního tlaku. Standardní Lagrangeovy konečné prvky byly porovnány s NURBS isogeometrickými elementy. Byly uvažovány prvky prvního a druhého řádu.
Comparative study of finite element method, isogeometric analysis, and finite volume method in elastic wave propagation of stress discontinuities
Berezovski, A. ; Kolman, Radek ; Blažek, Jiří ; Kopačka, Ján ; Gabriel, Dušan ; Plešek, Jiří
A comparative study of Finite Element Method, Isogeometric Analysis, and Finite Volume Method in numerical simulation of one-dimensional wave propagation problems of stress discontinuities in elastic solids is presented. The special attention is paid to accuracy, convergence, and stability of tested numerical methods and the appearance of spurious oscillations and damping effects occurring close to theoretical sharp wavefronts.
On the diminishing of spurious oscillations in explicit finite element analysis of linear and non-linear wave propagation and contact problems
Kolman, Radek ; Cho, S.S. ; Park, K.C.
A nearly non-spurious oscillations explicit time integration scheme for finite element solution of linear and non-linear wave propagation of stress discontinuities in solids and contact problems is presented and tested. The main concept of the diminishing spurious oscillations time scheme is based on a modification of the conventional central difference method.
Component-wise partitioned finite element method in linear wave propagation problems: benchmark tests
Kolman, Radek ; Cho, S.S. ; Červ, Jan ; Park, K.C.
A novel explicit time scheme for nite element computations of wave propagation problems in solids is presented. The presented algorithm, with the component-wise partition of equations of motion to the longitudinal and shear parts, is designed to more precisely integrate wave propagation in accordance with their dierent propagation wave speeds. The suggested three-time step integrator is fully explicit with the diagonal mass matrix, of second-order accuracy, conditionally stable and it exhibits minimal sensitivity behavior on time step size satisfying the stability limit. We present two numerical tests of wave propagation phenomena to show accuracy and performance of the proposed method.
An explicit time integration algorithm for finite element computations of discontinuous wave propagation problems
Kolman, Radek ; Cho, S.S. ; Park, K.C.
A novel explicit integration algorithm in the predictor-corrector form for finite element computations of discontinuous wave propagation problems in solids is presented. The nominated algorithm, with the component-wise partition of equations of motion to longitudinal and shear parts, is designed to more precisely integrate wave propagation in accordance with their dierent propagation wave speeds and their stability limits.
EUROMECH Colloquium 540 - Advanced Modelling of Wave Propagation in Solids
Kolman, Radek ; Berezovski, A. ; Okrouhlík, Miloslav ; Plešek, Jiří
The Euromech Colloquium 540 - Advanced Modelling of Wave Propagation in Solids took place at the Institute of Thermomechanics in Prague from 1st to 3rd October 2012. It aimed at bringing together engineers and scientists interested in modelling of wave propagation in solids. The Colloquium focused on topics related to effects in linear and non-linear wave propagation in solids. Recent advances in numerical and analytical approaches and strategies were discussed. The main purpose of the Colloquium was to discuss novel methods of wave propagation modelling and to assess the credibility of results especially in cases when experiment validation had not been available.
Frictionless contact of elastic bodies: comparison of treatment in finite element analysi and isogeometric analysis
Kopačka, Ján ; Kolman, Radek ; Gabriel, Dušan ; Plešek, Jiří
Artificial oscillations in contact force due to non-smooth contact surface are treated by isogeometric analysis (IGA). After brief overview of B-splines and Non-Uniform Rational B-Splines (NURBS) representation, the mortar-based contact algorithm is presented in the frictionless small deformation regime. Contact constraints are regularized by penalty method. The contact algorithm is tested by means of contact patch test.
Mass lumping methods for the semi-loof shell element
Sháněl, Vít ; Kolman, Radek ; Plešek, Jiří
Mass matrix diagonalization in terms of a finite element method (FEM) is essential for an effective deployment of the explicit method as one of the direct integration methods of the motion equations of elastodynamics. A particular attention is focused on the mass matrix diagonalization of the semi-loof shell element. Its diagonalization requires a specially designed universal diagonalization scheme that is derived from the scaling HRZ method. Another analyzed aspect is the problem of preserving the moment of inertia for various types of finite elements. The proposed scheme is implemented in the finite element program and consequently tested on several problems
Estimation of the critical time step for explicit integration
Plešek, Jiří ; Kolman, Radek ; Gabriel, Dušan
Explicit integration plays a key role in many problems of linear and non-linear dynamics. For example, the finite element method applied to spatial discretization of continua leaves a system of ordinary differential equations to be solved, which is often done by the central difference method.

Národní úložiště šedé literatury : Nalezeno 49 záznamů.   začátekpředchozí25 - 34dalšíkonec  přejít na záznam:
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