National Repository of Grey Literature 49 records found  beginprevious25 - 34nextend  jump to record: Search took 0.02 seconds. 
Internal corporate methodology for optimal dimensioning and utilization of screw joints
Pařík, Petr ; Kolman, Radek ; Gabriel, Dušan
The report summarizes the internal methodology for the optimum design of screw connections according to standard VDI 2230.
Isogeometric contact analysis: a study of an explicit dynamic contact algorithm
Kopačka, Ján ; Gabriel, Dušan ; Kolman, Radek ; Plešek, Jiří
The isogeometric NURBS based variant of symmetry preserving explicit FE contact-impact algorithm, has been proposed. The algorithm was studied by means of a numerical example, which involves 2d frictionless dynamic Hertz contact problem of two equally shaped cylinders. The attention was paid to the influence of different lumping techniques on the oscillations of contact force and contact pressure. The standard Lagrange finite elements were compared with the NURBS isogeometric elements. Both the first and second order were considered.
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.

National Repository of Grey Literature : 49 records found   beginprevious25 - 34nextend  jump to record:
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1 Kolman, R.
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