Wyniki wyszukiwania - BazTech

1

Szacowanie odporności udarowej okrętu z wykorzystaniem symulacji komputerowej

Flis L.

Logistyka

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2014

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nr 6

650--654, CD 2

PL

Omówiono przesłanki, wyboru metody Lagrange’a do modelowania odporności udarowej okr ę tu. Przedstawiono wyniki szacowania odporności udarowej okrętu obciążonego ciśnieniem od niekontaktowego wybuchu podwodnego z wykorzystaniem uproszczonego modelu dyskretnego uproszczonego. Odniesiono uzyskane wyniki do eksperymentu.

EN

Discusses the rationale, choose the method of Lagrangian modeling of the impact resistance of the ship. Presents the results of estimating the impact resistance of the ship loaded with pressure from non- contact underwater explosion using a simplified model of a discrete simplified. They referred to the results of the experiment.

2

Modelling the dynamics of flexible and rigid fibres

Kondora G., Asendrych D.

Chemical and Process Engineering

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2013

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Vol. 34, nr 1

87--100

EN

A particle-level simulation technique has been developed for modelling fibre suspension flow in a converging channel of a papermachine headbox. The fibre model is represented by a chain of elements connected together. The model was verified by the simulation of rigid fibre dynamics in a simple shear flow. The period of rotation was found to be in a very good agreement with theory and reference data. The model was then employed to simulate fibre motion in a converging channel of a papermachine headbox. Fibre suspension motion was resolved using two-step procedure. Velocity field was calculated by means of a commercial CFD code ANSYS Fluent with RSM turbulence model applied and used as an input to the in-house code allowing to simulate fibre dynamics. Results of the calculations were used to construct the fibre orientation probability distribution (FOPD) which was found to be consistent with available experimental data.

3

Numerical Simulations of Penetration of 9 mm Parabellum Bullet into Kevlar Layers : Erosion Selection in Autodyn Program

Wiśniewski A., Pacek D.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2011

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Vol. 2, Nr 3 (5)

11-20

EN

A numerical model was performed of penetration of 9 mm Parabellum bullet into Kevlar layers, with the use of the AUTODYN software program. Simulations were conducted with a bullet modelled by means of the Smooth Particle Hydrodynamicsmethod (SPH) and with an armour coded by a Lagrange grid. The simulations were performed for 20 layers of Kevlar (one layer: thickness - 0.3 mm, surface density - 220 g/cm²) and for impact velocity of 350 m/s. The comparison included the mean velocity of the bullet (which takes into account the velocities of particles that separated from the part of the bullet penetrating the armour) and the velocities at gauge points established near the axis of symmetry of the bullet. The gauge point representative for velocity of the bullet was indicated. With regard to excessively large deformations of the grid, that caused interruption of the initial simulation, the criteria of erosion (cells removal) were introduced. From effective strains available in the AUTODYN software, the effective instantaneous geometric strain was selected. Influence of the erosion strain (value of strain for which cells are removed) onto the mass of removed cells and the residual velocity of the bullet were investigated. Simulations with neglect and respect to mass of removed cells in further calculations were performed. The erosion criteria for which further simulations should be conducted were indicated.

4

One-dimensional numerical simulation of transient flow in a turbine stage.

Uzunow N.

Archive of Mechanical Engineering

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2005

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Vol. LII, nr 3

283-298

EN

The investigation presented in this work concerned one-dimensional modelling of transient flow in an axial turbine stage. Because of the compound motion in the rotor-blade channels, the model of this flow path element was considered the most difficult to solve. The basic modelling approaches and the usefulness of the Euler and Lagrange methods for mathematical description are discussed. Relevant applied model based on the Lagrange method is described. Results of a successful numerical simulation of transient flow in a turbine stage are presented. This success opens the opportunity to build and solve one-dimensional models of dynamic flows in turbine cascades and entire flow paths.

PL

Przedstawiono badania nad jednowymiarowym modelowaniem nieustalonych przepływów przez osiowy stopień turbinowy. Z powodu złożonego ruchu w kanałach wirujących, model tego elementu układu przepływowego turbiny uznano za najtrudniejszy do rozwiązania. Omówiono podstawowe podejścia przy modelowaniu oraz przydatność metod opisu matematycznego Eulera i Lagrange'a. Opisano odpowiedni model stosowany, oparty na metodzie Lagrange'a. Przedstawiono wyniki udanej symulacji numerycznej nieustalonego przepływu przez stopień turbinowy. Sukces ten stwarza możliwość budowy i rozwiązania jednowymiarowych modeli kaskad turbinowych i całkowitych układów przepływowych turbin do badania zachodzących w nich procesów nieustalonych.