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Recent progress in numerical methods for explicit finite element analysis
Kolman, Radek ; Kopačka, Ján ; Gonzalez, J. ; Gabriel, Dušan ; Cho, S.S. ; Plešek, Jiří ; Park, K.C.
In this paper, a recent progress in explicit finite element analysis is discussed. Properties and behaviour of classical explicit time integration in finite element analysis of elastic wave propagation and contact-impact problems based on penalty method in contact-impact problems are summarized. Further, stability properties of explicit time scheme and the penalty method as well as existence of spurious oscillations in transient dynamics are mentioned. The novel and recent improving and progress in explicit analysis based on a local time integration with pullback interpolation for different local stable time step sizes, bipenalty stabilization for enforcing of contact constrains with preserving of stability limit for contact-free problems and using a direct inversion of mass matrix are presented. Properties of the employed methods are shown for one-dimensional cases of wave propagation and contact-impact problems.
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Development, assessment and verification of finite element procedures for contact problems
Gabriel, Dušan ; Kopačka, Ján ; Masák, Jan ; Plešek, Jiří
A frictionless three-dimensional contact algorithm based on the pre-discretization penalty formulation was proposed. The algorithm proved to be robust, accurate and symmetry preserving—no master/slave surfaces have been introduced. It was implemented in the finite element code PMD (Package for Machine Design) for the solution of complex engineering problems. The capability of the algorithm was demonstrated in creep analysis of T-piece of the steam distributor of the CHEMOPETROL heating plant T200. Material properties were described by the probabilistic exponential model with damage. The purpose of the analysis was to compare the original version and the proposed design modification applied to one of T-pieces of the distributor when the proposed contact algorithm was employed to simulate the interaction between the collar and the pipe.
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Creep analysis of HP inner casing DSPWR – contact task
Kopačka, Ján ; Masák, Jan ; Gabriel, Dušan ; Plešek, Jiří
The report summarizes results of the 3rd stage of the creep analysis of Doosan Škoda Power high-pressure inner casing. An analysis of the high-pressure inner casing is carried out with respect to the contact boundary conditions in the division plane and the use of a complex creep material model. The results of the PMD contact analysis are compared to the measured values and also compared with the ANSYS program where the Norton-Bailey model of creep was used.
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Explicit dynamic finite element analysis of a firing pin assembly
Mochar, Dominik ; Gabriel, Dušan ; Masák, Jan ; Kopačka, Ján ; Kolman, Radek ; Plešek, Jiří ; Hynek, P. ; Vtípil, J.
In this paper, explicit dynamic finite element analysis of a firing pin assembly was performed. Two different geometries of the firing pin were considered using the finite element software PMD and Abaqus. For both variants there was evaluated a stress distribution at the critical point of a tested component, that is going to be later used for a fatigue analysis of the firing pin.
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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.
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