Wyniki wyszukiwania - Biblioteka Nauki

1

Numerical and experimental study on aluminium pipe bending process

100%

Domanowski P. , Nowak B.

Journal of Polish CIMAC

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2011

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tom Vol. 6, no 3

33-42

EN

In this paper the analysis of cold working bending process of the aluminum pipe was presented based on both numerical simulations and experimental tests. The parameters such as wall thickness above and below bending axis were compared and discussed for both numerical simulations and experimental tests. The numerical simulations were performed in Abaqus 6.9/CAE computational environment on the basis of finite element method while the bending machine was designed and constructed for the purpose of tests. The usefulness of numerical simulations was also discussed.

2

Development and growth of Temora longicornis: numerical simulations using laboratory culture data

80%

Dzierzbicka-Głowacka L. , Lemieszek A. , Żmijewska I. M.

Oceanologia

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2011

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tom No. 53 (1)

137-161

EN

Quantitative expressions are presented to describe the effects of temperature and food concentration on stage duration and growth rate of Temora longicornis for each of the model stage groups (N1-N6 - naupliar stages, C1, C2, C3, C4, C5 - the five copepodid stages). The calculations were made on the basis of experimental data from the literature for Temora longicornis from the south-eastern and the southern North Sea. Relationships were obtained between the growth parameters and temperature for the 5-10°C temperature range and food concentrations from 25 mgC m-3 to excess. Also computed was the total mean development time as a function of the above-mentioned parameters, temperature and food availability. The simulations computed here are similar to the experimental results. The growth rates for successive stages were obtained according to the correction of the "Moult Rate" method, which allows the use of mean weights and stage durations. The calculations also suggest that three complete generations of T. longicornis from the Gdańsk Deep (the southern Baltic Sea) can develop during a single year.

3

Computer - aided design of relaxing holes in the medium voltage products made of epoxy resin

80%

Ambroziński M. , Nowak T.

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tom Vol. 12, No. 4

225--232

EN

The aim of the presented work was to use computer simulation tools for studying exploitation of medium voltage epoxy resin devices. Locations where the stress concentration occurred as a result of thermal expansion were examined. These stress concentrations usually lead to the crack initiation and propagation and to failure of the part. Relief holes are applied in practice to involve stress relaxation and prevent failure. Application of two relief holes for the part made of two materials is described in the paper. The sample has steel core and resin sleeve. This composition was selected due to large difference in properties of components and due to serious problems it creates during exploitation. Prediction of the best locations of the relief holes in this material was a particular objective of the work. The results obtained from 2D and 3D numerical simulations and experiments are presented in the paper.

PL

Celem pracy była weryfikacja metody redukcji poziomu naprężeń szczątkowych, występujących po procesie produkcyjnym, poprzez zastosowanie otworów odprężających. Obiektem badań był model reprezentujący urządzenie średniego napięcia, składający się metalowego rdzenia oraz zewnętrznej izolacji odlanej z żywicy epoksydowej. Wykorzystano analizy numeryczne do wskazania optymalnej geometrii otworu odprężającego, oraz jego usytuowania względem karbu. Przeanalizowano dwa różne warianty konstrukcyjne (stosując otwory wiercone oraz odlewane). Wyniki symulacji numerycznych posłużyły do zaprojektowania próbek testowych, które poddano badaniom eksperymentalnym. Na podstawie przeprowadzonych analiz możliwe było wyciągnięcie wniosków praktycznych i rekomendacji dla stosowania metody otworów odprężających w produkcji aparatów średniego napięcia. W szczególności wykazano, że prawidłowe zastosowanie w/w metody przynosi pozytywne efekty, nawet w przypadku materiałów kruchych, jakimi są żywice epoksydowe

4

Analysis of Flowing Fluid Effect on Flow Averaging Tube

80%

Kabaciński M. , Lachowicz C. , Pospolita J.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2008

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tom Vol. 12, No 3-4

217-226

EN

This paper presents a mathematical model and results of numerical simulations for a fluid flow around a flow averaging tube. The calculations have been performed using the commercially available FLUENT software. The authors have applied the currently known studies of the models of turbulence and their applicability in certain flow conditions and hence selected the RNG k-epsylon turbulence model including appropriate functions to be used for determination of pressures and velocities at the sites of occurrence of considerable gradients. The distributions of pressures and velocities around a sensor are presented along with pressure distributions, instantaneous and averaged in time, on the measuring tube surface. The paper determines the frequencies of measuring tube free vibrations for one sided and two-sided tube fitting for the tube length in the range 100–1500mm. This analysis has been conducted with the aid of solving equations for free undamped vibrations for specific models. The graphical presentation involves an admissible range of tube lengths with one and two-sided fitting for the specified flowing air velocities.

5

Numerical analysis of an impact of planned location of sewage discharge on Natura 2000 areas – the dead Vistula region case study

80%

Zima P.

Polish Maritime Research

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2019

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tom nr 2

76--84

EN

This article presents results of an analysis of impact of a designed discharge of contaminated water into the Dead Vistula (Wisła Martwa) in the region of the Isthmus (Przesmyk) with the aim of determination of a possible effect of the pollution onto protected areas of Natura 2000 (bird habitats and sites, especially the Bird Paradise – Ptasi Raj) nature reserve. The analysis was conducted on the basis of the two-dimensional modelling of unsteady transport of non-degradable dissolved matter. To this end, a numerical model of a section of the Dead Vistula was worked out. Four scenarios of hydro-dynamical conditions (2 – for average weather conditions and 2 – for stormy weather conditions) were selected. To solving the equation of pollution migration the finite volumes method (MOS) was applied. Two localizations of contaminated water discharge outlet were considered, namely: the first from the side of Siennicki Bridge before the Isthmus and the other in the section of the Brave Vistula (Wisła Śmiała) downstream the Isthmus. The obtained results made it possible to assess positively the first localization of the designed discharge outlet. In the other case there is a fear that at unfavourable hydro-meteorological conditions a water pollution may happen over Natura 2000 protected areas.

6

Robust synchronization of chaotic fractional-order systems with shifted Chebyshev spectral collocation method

80%

Owolabi K. M.

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2021

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tom Vol. 27, nr 2

269--282

EN

In this work, synchronization of fractional dynamics of chaotic system is presented. The suggested dynamics is governed by a system of fractional differential equations, where the fractional derivative operator is modeled by the novel Caputo operator. The nature of fractional dynamical system is non-local which often rules out a closed-form solution. As a result, an efficient numerical method based on shifted Chebychev spectral collocation method is proposed. The error and convergence analysis of this scheme is also given. Numerical results are given for different values of fractional order and other parameters when applied to solve chaotic system, to address any points or queries that may occur naturally.

7

Analysis of fiber orientation in the wood-polymer composites (WPC) on selected examples

80%

Frącz W. , Janowski G.

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2017

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tom Vol. 11, no 3

122--129

EN

The fibers orientation in the polymer matrix is an important factor determining mechanical properties of products made of composites by means of an injection molding process. The fibers arrangement has an effect on shrinkage of the composite and the dimensional accuracy of molded piece. The knowledge of fiber orientation can determine the proper dimensions and design of the molding cavities and then correct some of physical and mechanical properties of the molded piece. The orientation of fillers depends on many factors, among which the important role play processing parameters including the injection speed. The aim of this study was to assess the orientation of the fibers in wood-polymer composite on the selected examples. The knowledge and proper use of micromechanical models allow to evaluate the fibers flow and their orientation in polymer matrix. The research was performed both for numerical simulations and experimental studies for results verification.

8

Numerical methods for fast magnetoacoustic waves in solar coronal loops

80%

Gruszecki M. , Murawski K.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2009

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tom Vol. 13, No 1-2

75-81

EN

Numerical methods for standing fast magnetoacoustic kink waves in an isothermal solar coronal slab with a field aligned flow are considered. Such waves are triggered impulsively by a velocity pulse that is initially launched in an ambient medium. The spatial and temporal signatures of these waves are determined by solving two-dimensional, ideal magnetohydrodynamic equations numerically. The Ramses code which resolves complex spatial structures by adopting an adaptive mesh refinement technique and shock-capturing capabilities is used. The numerical results show that spatial and temporal wave signatures are reminiscent to the recent observational findings.

9

Evaluation of the jet damping effect on flight dynamics of a homing guided missile

80%

Kowaleczko G.

Journal of Theoretical and Applied Mechanics

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2016

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tom Vol. 54 nr 3

893--907

EN

The paper presents evaluation of the jet damping effect on spatial motion of a homing guided missile with variable mass. The mathematical model of motion including effects generated by the burning fuel are presented – changes of mass characteristics as well as the jet damping effect are taken into account. Both the influences of inertia forces/moments and changes of the position of mass center are calculated. The damping effect generating additional forces and moments acting on the missile is also determined. The obtained set of equations of motion allows one to analyze a wide spectrum of various problems, e.g. the influence of jet damping on the homing guided missile trajectory or the dynamic response of the missile to atmospheric disturbances. Exemplary results of simulations are shown.

10

Influence of Liquid Metal Movements on the Casting Creation

80%

Sowa L. , Skrzypczak T. , Kwiatoń P.

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2021

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tom Vol. 66, iss. 2

489--495

EN

Knowledge about complex physical phenomena used in the casting process simulation requires continuous complementary research and improvement in mathematical modeling. The basic mathematical model taking into account only thermal phenomena often becomes insufficient to analyze the process of metal solidification, therefore more complex models are formulated, which include coupled heat-flow phenomena, mechanical or shrinkage phenomena. However, such models significantly complicate and lengthen numerical simulations; therefore the work is limited only to the analysis of coupled thermal and flow phenomena. The mathematical description consists then of a system of Navier-Stokes differential equations, flow continuity and energy. The finite element method was used to numerically modeling this problem. In computer simulations, the impact of liquid metal movements on the alloy solidification process in the casting-riser system was assessed, which was the purpose of this work, and the locations of possible shrinkage defects were pointed out, trying to ensure the right supply conditions for the casting to be free from these defects.

11

Analysis of the inadequacy of determining the spectral characteristics of optical fibre periodic structures by way of numerical modelling

80%

Stępniak P. , Kisała P.

Metrology and Measurement Systems

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2020

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tom Vol. 27, nr 1

33--50

EN

As part of the work, the error level of simulations of uniform optical-fibre Bragg gratings was determined using the transition matrix method. The errors were established by comparing the transmission characteristics of the structures obtained by simulation with the corresponding characteristics arrived at experimentally. To compile these objects, elementary properties of the characteristics were specified, also affecting the applications of Bragg gratings, and compared with each other. The level of error in determining each of these features was estimated. Relationships were also found between the size of the physical properties of Bragg gratings and the level of errors obtained. Based on the findings, the correctness of the simulation of structures with the said method was verified, giving satisfying results.

12

Numerical implementation of car impact into the modified road barrier

80%

Kiczko A. , Niezgoda T. , Nowak J. , Dziewulski P.

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tom Vol. 17, No. 3

189-196

EN

In previous works the research team submitted [1-5] a series of numerical analysis of the car - road barrier dynamical system, directed to the elaboration of the numerical model methodology of an impact problem with the use of the chosen CAE programs. In this article there are presented the results of works on numerical implementation of crash tests of a car with the modified road barrier. The results are presented on the example of the Suzuki Swift car impact into the road barrier, which is equipped with the additional protective panel. The panel consists of the foamed aluminium plate whose fastening to the belt of the W-beam guardrail and a shield presented itself a thin-walled open profile made from the polyester-glass laminate. The whole construction was connected with the W-beam guardrail by riveting. The Geo Metro (Suzuki Swift) car, commonly available model from National Crash Analysis Centre (NCAC), was used for numerical analysis of the car-barrier system. Numerical analysis was carried out with the use of LS-Dyna system. The comparison of the time courses of acceleration, acting on the vehicle centre of gravity and the ways of the barrier and car deformation, achieved by the experimental and simulation ways, took place. The good qualitative and quantitative conformities in accelerations w archieved.

13

Hybrid computer system for the design of flat rolling technology : case study for multiphase steel

80%

Rauch Ł.

Computer Methods in Materials Science

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2012

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tom Vol. 12, No. 3

218--224

EN

Creation of the system for optimization of semi product and product properties in metal forming industry was the objective of the paper. This system is demonstrated in application to Advanced High Strength Steels (AHSS), which are innovative materials used by automotive industry. The system joins functionality of numerical simulations, material modelling and optimization to minimize costs related to design of production technologies and maximize semi and final product properties The paper presents design and functionality of the hybrid computer system, which includes all mentioned functional modules for the design of flat rolling technology. The architecture of the proposed system is described in details as well as material models applied in numerical simulations. The system was validated and tested using optimization of multiphase cycle of rolling of complex phase steel strip as an example.

PL

Celem pracy było stworzenie systemu dla optymalizacji wytwarzania półwyrobów i wyrobów w przemyśle przetwórstwa metali. System przedstawiono w zastosowaniu do stali AHSS, które są nowoczesnymi materiałami wykorzystywanymi przez przemysł samochodowy. System łączy funkcjonalność symulacji numerycznych, modelowania materiałów oraz optymalizację, co pozwala na minimalizację kosztów związanych z projektowaniem technologii produkcyjnych oraz umożliwia uzyskanie optymalnych własności półwyrobów i wyrobów. Niniejszy artykuł przedstawia projekt i funkcjonalność hybrydowego systemu komputerowego, posiadającego wszystkie wymienione powyżej moduły funkcjonalne niezbędne do projektowania technologii walcowania wyrobów płaskich. Architektura zaproponowanego systemu została szczegółowo opisana, podobnie jak modele materiałowe wykorzystane w testowych symulacjach numerycznych. System został zweryfikowany dla przypadku optymalizacji cyklu walcowania produktów ze stali wielofazowych.

14

The analysis of the influence of a torsional vibration damper on transversal displacement of a crankshaft

80%

Chiliński B. , Dziurdź J. , Zawisza M.

Journal of KONES

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2016

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tom Vol. 23, No. 4

33--39

EN

The article presents a consideration of the influence of a damper of torsional vibrations (TVD) on transverse dynamics of the crankshaft. Dampers of this type work based on the dynamic eliminator of vibrations. The systems of this type in modern combustion engines are more often used to reduce torsional vibrations. It is strictly connected with the increase of fatigue life of the crankshaft in case when its amplitude of vibrations has a crucial meaning. Computation models used to choose a damper assume that transverse and torsional vibrations occurring in a crank system are not coupled. Modern trends in machine design make the new devices lighter and less rigid. Therefore, the couplings between small vibrations may be more important. Therefore, the effects observed in angular vibrations can be transmitted to transverse vibrations. In this context, the impact of dampers TVD on transverse dynamics is particularly interesting. In the introduction, the article discusses the basic types of torsional vibration dampers and the method of selection of this type of systems. The next part of the article presents the model of a combustion engine with a dynamic eliminator of vibrations, which includes bending-torsional vibrations occurring in the system. For this purpose, the linear relation of the vector of generalized co-ordinates and generalized forces in the system was assumed. The next part shows numerical simulations, which were carried out in the paper. The paper presents obtained results with their further analysis in frequency domain. The whole paper is summarized with synthetic conclusions on the simulations, the impact of applied eliminator on the dynamics of the entire crank system, in particular transverse vibrations. In addition, there was indicated a possibility of using presented results in research and diagnostics used in automotive industry of torsional vibration dampers.

15

Analysis of the inadequacy of determining the spectral characteristics of optical fibre periodic structures by way of numerical modelling

80%

Stępniak P. , Kisała P. , Stępniak P. , Kisała P.

|

16

Influence of Liquid Metal Movements on the Casting Creation

80%

Sowa L. , Skrzypczak T. , Kwiatoń P. , Sowa L. , Skrzypczak T. , Kwiatoń P.

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nr 2

17

Use of the MBS method in mining industry R&D projects

80%

Szewerda K. , Krenicky T.

Mining Machines

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2022

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tom vol. 40, iss. 2

110--120

EN

Virtual prototyping methods are an important aspect both in the designing process and in research processes aimed at the modification and optimization of machines and devices. It allows one to analyse the way of operation, the flow of forces, the cooperation between components, as well as finding the weakest points of the structure. This article presents the possibilities of using the MBS method, which is one of the tools used in virtual prototyping, on the basis of the results of R&D projects realized at the KOMAG Institute of Mining Technology. The main objective of the MBS method is to simulate the kinematics and dynamics of multi-body systems, the results of which will enable a series of analyses related to the operation of machines and devices.

18

Experimental research and numerical analysis of penetration of the twaron T750 aramid fabric with the 9 mm Parabellum projectile

80%

Wiśniewski A. , Pacek D.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2013

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tom Vol. 4, Nr 3 (13)

7-22

EN

The paper presents results of experimental research and numerical analysis of the penetration process of the Twaron T750 aramid fabric with the 9 mm Parabellum projectile (brass jacket, lead core). Numerical simulations of the 9 mm Parabellum projectile impact into 10 and 16 layers of the Twaron T750 fabric with the use of the Ansys Autodyn v13 program for dynamic analyses were conducted on the basis of 3-dimensional solid numerical models. As a boundary condition in the experiment and in the numerical simulations it was assumed that all the four edges of the fabric were fixed. In the numerical simulations the sample of 50 ×50 mm dimensions and the impact velocities Vi = 448 m/s for 16 layers of the Twaron T750 fabric and Vi = 454 m/s for 10 layers of Twaron T750 fabric were adopted. In the paper the results of the numerical simulations for three material configurations with the same friction coefficients and for different values of yarn-yarn friction in case of one material configuration are presented. Residual velocity of the penetrator for the highest friction coefficient μs = 1 decreased of 13.1% in comparison to simulation with no friction (μs = 0).

19

Modeling and Experimental Verification of Ultrasound Transmission in Electro Insulation Oil

80%

Wotzka D. , Cichoń A. , Boczar T.

Archives of Acoustics

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2012

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tom Vol. 37, No. 1

19-22

EN

A verification study of ultrasound transmission numerical simulation results with experiment results is presented in this paper. The work considers a model of a transformer tank which is filled with electro insulating oil. In the experiment, performed under laboratory conditions, an ultrasound wave is generated by a piezoelectric transducer that is fixed in the centre of the tank and measured by another transducer mounted inside the tank at three distances: 10, 20 and 30 cm from the sound source. The transducer is able to measure and generate acoustic waves in the ultrasound frequency band up to 1 MHz. The simulation considers numerical calculation of acoustic pressure distribution inside the tank in which acoustic source emits waves with frequency equal to 100 kHz. Verification analysis has confirmed consistency of the numerically calculated values with the measurement results.

20

Searching for critical conditions during lifeboat launching – simulations

80%

Dymarski C. , Dymarski P. , Kniat A.

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tom S 1

53--58

EN

The article describes numerical simulations of the process of lifeboat launching at the ship’s side. The research aimed at finding the values of ship motion parameters which appear to be most dangerous for people in the lowered lifeboat due to the generated accelerations. The simplified model of ship hull motion adopted at this research stage bases on a superposition of harmonic motions with given amplitudes and periods in six degrees of freedom. The range of the amplitude of motion for each degree of freedom corresponds approximately to that of possible motion of the PANAMAX type ship on the Baltic sea. In total, 120 960 cases of ship hull motion were examined.