Autor: Małachowski, J. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: I-beam structure under blast loading-Eulerian mesh density study
Autorzy:: Mazurkiewicz, Ł.
Małachowski, J.
Powiązania:: https://bibliotekanauki.pl/articles/245483.pdf
Data publikacji:: 2011
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: blast wave
FEM
Eulerian mesh
Opis:: Dynamic response of an I-beam structure subjected to shock wave produced by the detonation of high explosive (HE) materials is presented in this paper. LS-DYNA, a 3-D explicit, finite element computer code is used to study this behaviour. A coupled analysis between Lagrangian formulation (solid material) and Eulerian formulation (gas medium) was performed. The latest extensive research in this area indicates that the finite element analyses of such problems require complex meshes for Euler and Lagrange formulation. This research is focused on Euler mesh density influence on coupled analysis results. The principal objective of this paper is to compare various mesh density Eulerian models in respect to accuracy and computing time and asses the limit of element size. The Eulerian domains (Air and HE) were developed with various element size from 10 mm up to 30 mm. Results from all the analysis cases show how the Eulerian mesh element size influences on the global response of the column. Models with coarse meshes give much lower dynamic response then models with finer meshes. The resultant velocity vectors were also presented to illustrate the characteristic of blast wave propagation. Moreover the numerical models computational efficiency was compared are respect of CPU Time. Models with complex meshes (below 20 mm) are very computationally expensive.
Źródło:: Journal of KONES; 2011, 18, 3; 245-252
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Analysis of selected structural components subjected to blast wave
Autorzy:: Mazurkiewicz, Ł.
Małachowski, J.
Powiązania:: https://bibliotekanauki.pl/articles/248066.pdf
Data publikacji:: 2012
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: ALE formulation
blast wave
dynamic response
structural component
Opis:: The phenomenon of high-energy explosion of a substance such as the mixture of flammable gases, explosives, etc. is highly exothermic chemical reaction that causes a blast wave consisting of hot gases at high pressure. Very complex nature of the phenomenon of detonation, affects the need for advanced methods of analysis. In the present work analysis of two steel columns (I-section and tubular section) subjected to the blast wave are presented. The columns have similar values of the moments of inertia and mass per unit length. To describe the complex phenomena occurring in gas medium the Eulerian formulation was used. The steel structures were described using Lagrangian formulation. Interaction between domains was achieved by numerical coupling algorithm with implemented penalty function. From the results from all the analysis cases, the dynamic response of structural elements was obtained. Permanent deformation and the amount of absorbed energy are of special interest in this study. The resultant velocity vectors were also presented to illustrate the characteristic of blast wave propagation.
Źródło:: Journal of KONES; 2012, 19, 1; 267-272
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Comparison of numerical testing methods in terms of impulse loading applied to structural elements
Autorzy:: Mazurkiewicz, Ł.
Małachowski, J.
Baranowski, P.
Damaziak, K.
Powiązania:: https://bibliotekanauki.pl/articles/280777.pdf
Data publikacji:: 2013
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: blast wave
FEM
Eulerian mesh
Opis:: This paper presents comparison of numerical testing methods of an impulse loading which comes from a detonation process, i.e. blast wave propagation in a gas medium. Investigations were carried out using an analytical and numerical model based on the Finite Element Method. In order to reduce computational time, the substitute analytical model with one degree of freedom was implemented, which replaced a chosen actual system (I-section steel column). For structure modelling, the constitutive model was used, which included the strain rate effect. From the performed analyses, an acceptable similarity was noticed, although the discrete model due to greater forces gave inflated results. Nevertheless, it should be pointed out that simplified methods do not take any wave and flow around effects into consideration, which have an influence on the dynamical response of the structure and are possible to implement in the gas medium coupling.
Źródło:: Journal of Theoretical and Applied Mechanics; 2013, 51, 3; 615-625
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Dynamic testing of copper material : numerical approach
Autorzy:: Baranowski, P.
Małachowski, J.
Mazurkiewicz, Ł.
Damaziak, K.
Powiązania:: https://bibliotekanauki.pl/articles/387353.pdf
Data publikacji:: 2013
Wydawca:: Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:: miedź
sprężanie
analiza elementów skończonych
SHPB
copper
compression
FE analysis
Opis:: Split Hopkinson pressure bar (SHPB) is one of the most important and recognisable apparatus used for characterizing the dynamic behaviour of various materials. Incident pulse generated one the incident bar usually have a rectangular shape, which is proper for some materials but for others is not. Therefore, several methods of shaping the incident pulse are used for obtaining constant strain rate conditions during tests. Very often pulse shapers made of copper or similar material are implemented due to its softness properties. In this paper such material was investigated using the FE model of SHPB. Its mechanical behaviour was characterised with and without copper disc between the striker and incident bar. Numerical simulations were carried out using explicit LS-DYNA code. Two different methods were used for modelling the copper sample: typical finite Lagrangian elements and meshless Smoothed Particle Hydrodynamics (SPH) method. As a result of two techniques used axial stress-strain characteristics were compared for three different striker’s velocity with an influence of the copper pulse shaper taking into account. Finally, FE and SPH method was compared with taking into consideration: the efficiency, computer memory and power requirements, complexity of methods and time of simulation.
Źródło:: Acta Mechanica et Automatica; 2013, 7, 4; 195-202
1898-4088
2300-5319
Pojawia się w:: Acta Mechanica et Automatica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Identification of layers distribution in the composite coupon using finite element method and three point bending test
Autorzy:: Mazurkiewicz, Ł.
Małachowski, J.
Damaziak, K.
Baranowski, P.
Gotowicki, P.
Powiązania:: https://bibliotekanauki.pl/articles/387164.pdf
Data publikacji:: 2013
Wydawca:: Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:: fibre reinforced composite
FE analysis
hand lay-up technique
experimental validation
kompozyt włóknisty
analiza elementów skończonych
weryfikacja doświadczalna
Opis:: The main objective of the study is to develop experimentally validated FE model and perform numerical analysis of layered composites made by hand lay-up techniques during tension and bending test. The research object is glass - polyester laminate made of four unidirectional layers. In order to validate the numerical models experimental test were performed. Due to the very different stiffness modulus in tension and bending loading the material properties obtained from standard test are not suitable to apply in numerical model. Significantly different behaviour compared to experimental test was obtained for tree point bending where the numerical model becomes too stiff. Simple coupons, relatively easy to manufacture presented in the paper have very low quality. The differences in actual and theoretical bending stiffness (obtained from tension stiffness) exceed 70%. In order to represent the actual structure the layers of the composite were divided by resin layers and also additional resin layer at the top and bottom of the model were defined. Single stage optimization process was used to adjust the material layout. After layer set-up modification very significant improvement can be seen for flexural behaviour.
Źródło:: Acta Mechanica et Automatica; 2013, 7, 3; 160-165
1898-4088
2300-5319
Pojawia się w:: Acta Mechanica et Automatica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Numerical analysis of I-beam supporting structure with multimaterial protective panel - parametric study
Autorzy:: Damaziak, K.
Mazurkiewicz, Ł.
Małachowski, J.
Klasztorny, M.
Baranowski, P.
Powiązania:: https://bibliotekanauki.pl/articles/246508.pdf
Data publikacji:: 2012
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: ALE formulation
blast wave
dynamic response
protective panel
Opis:: Dynamic response of an I-beam supporting structure subjected to shock wave produced by the detonation of high explosive materials is presented in this paper. Dynamic response of structural components in different load cases-with multimaterial panel protection and without protection, subjected to blast wave from various charge weight and various distance stand-off was determined. LS-DYNA, a 3-D explicit, finite element computer code with Lagrangian-Eulerian coupling was used to study this behaviour. Also initial static load was taken into account as pre-stress field present in the column obtained using dynamic relaxation procedure. The protective panel is composed of fibreglass composite and aluminium foam. The composite orthotropic properties and the failure criteria for fibre and matrix damage as well as the stress-volumetric strain curve for metallic foam were taken into account. The previous study shows that critical to the structure durability are the plastic strains and the structure failure caused by high deformation. Results of the analyses indicate that application of the blast panel around the supporting structure increase the resistance and significantly reduce the plastic deformation of the structure. The pillar without protection can be destroyed by 2 kg TNT placed close to the structure. Analysed beam covered by the blast panel can resist over three times bigger charge without significant deformation of the structure.
Źródło:: Journal of KONES; 2012, 19, 3; 93-102
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Badania numeryczne procesu zderzenia siatki obezwładniającej i ciała sztywnego w locie
Numerical Tests of Impact Process Between Net Structure and Rigid Object During Flight
Autorzy:: Baranowski, P.
Bukała, J.
Damaziak, K.
Małachowski, J.
Mazurkiewicz, Ł.
Niezgoda, T.
Powiązania:: https://bibliotekanauki.pl/articles/403883.pdf
Data publikacji:: 2013
Wydawca:: Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
Tematy:: mechanika
modelowanie MES
dynamika
mechanics
FEM modelling
dynamics
Opis:: Artykuł przedstawia proces dynamicznego oddziaływania pomiędzy siatką obezwładniającą a modelowym obiektem charakteryzującym się stosunkowo małymi wymiarami geometrycznymi i małą masą. Zarówno siatka, jak i rozpatrywane ciało, posiadały prędkość postępową oraz obrotową. Do analiz przyjęto siatkę zbudowaną z wysokowytrzymałego materiału typu aramidowego, tj. Kevlar, Dyneema, o kształcie ośmiokąta składającego się z rombowych oczek. W celu odzwierciedlenia zniszczenia włókien siatki zastosowano kryterium zniszczeniowe w postaci odkształceniowej (bezpośrednio wynikającej z wydłużenia przy zerwaniu linki). Jednym z głównych uproszczeń przyjętych w testach jest fakt nieodkształcalności samego obiektu testowego, co oznacza badania skuteczności siatki w najcięższych możliwych warunkach z uwagi na ekstremalne wytężenie włókien siatki w trakcie dynamicznego kontaktu z doskonale sztywnym ciałem. Dynamiczne symulacje numeryczne przeprowadzono przy użyciu kodu obliczeniowego LS-Dyna, równania ruchu rozwiązywane są metodą bezpośrednią (metoda różnic centralnych). W konsekwencji sprawdzone zostały najbardziej istotne wartości, tj. tor lotu obiektu – zmiana jego trajektorii i prędkości oraz przeanalizowano zachowanie układu w czasie zderzenia i po jego zakończeniu.
Presented paper shows the modelling process of collaboration between net and chosen rigid object with relatively small geometric dimensions and low weight. Both, net and object had rotational and translational velocity applied. Octagon-shaped net structure with diamond mesh was modelled using high strength aramid type material Kevlar 49. In order to simulate the breach process of the net fibre the failure criterion was implemented. Dynamic simulations were performed using the explicit LS-Dyna code with central difference scheme with modified equation of motion time integration. From the carried out analyses the most essential parameters were investigated including object trajectory and velocity changes and also the behaviour and characteristics of netrigid object system were analysed before, during and after the impact, Additionally, a net span level, diameter of the net line and place of contact was analysed with particular attention pointed on their influence on the impacting rigid object.
Źródło:: Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa; 2013, 4, 1 (11); 59-76
2081-5891
Pojawia się w:: Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Multi - body simulations of railway wagon dynamics
Autorzy:: Wójcik, K.
Małachowski, J.
Baranowski, P.
Mazurkiewicz, Ł.
Damaziak, K.
Krasoń, W.
Powiązania:: https://bibliotekanauki.pl/articles/246886.pdf
Data publikacji:: 2012
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: multi-body
MSC ADAMS
railway wagon
dynamics
Opis:: The main aim of the presented paper is to verify the dynamics of chosen railway wagon using multi-body methods. Thus, in tests a wagon prototype with rotational rail-car body was simulated, which is going to be used for TIR vehicles trailer bodies transporting. Implemented prototype is authored by the team from Department of Applied Mechanics and Computer Science from Faculty of Mechanical Engineering in Military University of Technology. For this purpose CAD model, and subsequently numerical model, of mentioned wagon was developed. Using MSC Adams software initial boundary conditions, material parameters and contact characteristics were defined. In the previous authors' paper [1], preliminary analyses of the loads acting on the railway platform were carried out, which verified chosen parameters and coefficients. The main aim of presently proposed 3D multi-body simulations of railway wagon is to investigate its motion with full load and to determine the operation limit safety. Thus, in the performed analyses the railway wagon was accelerated to the desired velocity and drove through the curved tracks with four different velocities. From the carried out simulations the wagon dynamic behaviour was investigated and obtained results including contact forces characteristics were compared from all analyses cases. Moreover, performed study shows that the MSC. Adams software is capable for analysing and simultaneously validating various complex engineering problems, such as the one investigated by the authors.
Źródło:: Journal of KONES; 2012, 19, 3; 499-506
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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