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1

Schur complement method with iterative solver for 2D fieldcircuit coupling finite element problem with movement

Marcsa D., Kuczmann M.

Przegląd Elektrotechniczny

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2014

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R. 90, nr 12

145--148

EN

The analysis and design of electromechanical devices involve the solution of large sparse linear systems, and require therefore high performance algorithms. In this paper, the Schur complement method with parallel preconditioned conjugate gradient (PCG) solver is introduced in two-dimensional parallel time-stepping finite element formulation to analyse rotating machine considering the electromagnetic field, external circuit and rotor movement. The proposed parallel solver is analysed concerning its computational efficiency and number of iterations. Simulation results of a rotating machine are also presented.

PL

Analiza i projektowanie urządzeń elektromechanicznych zawierają rozwiązanie dużych układów równań z macierzami rzadkimi, i dlatego wymagają algorytmów o wysokiej wydajności. W artykule metodę uzupełnień Schura z algorytmem opartym na metodzie gradientów sprzężonych wprowadzono do dwuwymiarowego, równoległego, czasowokrokowego sformułowania elementów skończonych do analizy maszyny elektrycznej od strony pola elektromagnetycznego, obwodu elektrycznego zewnętrznego oraz ruchu wirnika. Proponowany równoległy algorytm został poddany analizie pod kątem jego wydajności obliczeniowej, oraz liczby iteracji. Rezultaty symulacji maszyny wirującej są także przytoczone.

2

Some selected FEM analyses of motion of a bullet with imperfections while interacting with the barrel

Łazowski J., Małachowski J.

Journal of KONES

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2008

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Vol. 15, No. 1

145-152

EN

The intended aim of studies on the modelling of a bullet interacting with a barrel is to generale a virtual, computer-based model, experimentally verified for some selected mating conditions, and to become able to predict -with strong probability - processes and phenomena that take place within a system with imperfections. In the case under consideration the problem of contact between the barrel and the bullet has been described with the calculation method based on the penalty function. Calculations were made using the so-called direct-integration procedurę, colloquially called the ,,explicit integration ". Preliminary analysis has been carried out on the effect of the shift of the centre ofmass of the bullet moving in the barrel. Simulation included the bullet displacement along the barrel's axis, with the assumed positions of the centre ofmass -5% and +5% as measured from the bottom and referred to the initial model (0%). Results ofnumerical calculations suggest the effect of shift of the bullet's centre of mass, which -when exposed to complex states of loading - experiences oscillating movements of the bottom and the tip. Additionally, this analysis proves that there is a complex state of stress due to compression, torsion, and bending of the bullet while interacting with the inner part of the barrel. Numerical solutions may support the analytically approached solving of such mechanical system. They may also offer more precise determination of, e.g. initial and boundary conditions for the bullet 's free flight, which is of great significance to the accuracy of fire, and therefore, to the weapons effectiveness.

3

Elements of Movement Modelling of Landyacht

Skórski W. W.

Machine Dynamics Problems

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2005

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Vol. 29, No. 3

59--72

EN

In case of any project, the stages of designing and studying used to be the most funds consuming, especially if traditional methods as test designing and carrying out are applied on a real model. Thus one of the best way to cut production costs is replacing the real model with a virtual one. However, in the present article we are going to analyse dynamic of landyacht: a wind-sail-propelled machine with wheels, driven by a man. In our case it will be a three-wheel vehicle with a torsional (steering) front wheel. The movement was simulated in ADAMS system, using results of weight measurement tests of aerodynamic forces of landyacht model, executed in the aerodynamic tunnel in Institute of Aeronautics and Applied Mechanics of Warsaw University of Technology. The tunnel measurements were completed for a landyacht model with sails in the scale of 1:6. Resulted coefficients of aerodynamic forces were used for verification equations of motion and modelling of aerodynamic forces and resistance working on landyacht in ADAMS system.