Wyniki wyszukiwania - Biblioteka Nauki

1

Ochrona załogi pojazdu wojskowego przed wybuchem min i improwizowanych urządzeń wybuchowych (IED)

100%

Sławiński G. , Niezgoda T.

Journal of KONBiN

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2015

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tom No. 1 (33)

113--122

PL

W wyniku eksplozji pod pojazdem militarnym wzrasta ryzyko zagrożenia życia i zdrowia załogi. Rozpatrywanie tego zdarzenia pod kątem bezpieczeństwa żołnierzy sprowadza się do złożonej analizy wzajemnych oddziaływań ciała żołnierza, siedziska i elementów konstrukcji pojazdu. W efekcie działania fali uderzeniowej występują oddziaływania powodujące drgania wynikające z wibracji konstrukcji oraz przyspieszenie ciała pasażera. W pracy podjęto próbę analizy wpływu eksplozji improwizowanego ładunku wybuchowego (IED) pod pojazdem militarnym na ryzyko powstania urazów kręgosłupa szyjnego żołnierzy. Analiza została wykonana z wykorzystaniem metod numerycznych w programie LS-DYNA i prowadzona była uwzględniając zmienne wartości przemieszczenia oraz przyspieszenia rejestrowane podczas wybuchu.

EN

Risk of danger for military vehicle crew life and health increases when explosion under vehicle appears. Consideration of this phenomenon in the aspect of soldiers safety is based on coupled analysis of soldier's body, car seat and vehicle construction elements. As the effect of blast wave interaction the vibrations of construction and passenger body acceleration appear. In the paper the analysis of improvised explosive device (IED) detonation under the military vehicle was carried out in the aspect of soldier neck spine injury. The analysis was made with the usage of numerical methods in LS Dyna computer code and considered the changeble values of displacement and acceleration registered during detonation.

2

Numerical analysis of the riveted specimen

100%

Szymczyk E. , Sławiński G.

Journal of KONES

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2007

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tom Vol. 14, No. 2

475-484

PL

Połączenia nitowe są krytycznymi obszarami w konstrukcji lotniczej, ze względu na występowanie wtórnego zginania, koncentracji naprężeń oraz odkształceń plastycznych. Analiza konstrukcji lotniczych, w tym połączeń nitowych wymaga zastosowania lokalno-globalnego podejścia do modelowania numerycznego. W artykule przedstawiono analizę powłokowo-belkowego modelu połączenia zakładkowego złożonego z dwóch blach aluminiowych połączonych sześcioma nitami. Do opisu nitów zastosowano elementy belkowe. Uwzględniono zjawisko kontaktu oraz tarcie pomiędzy współpracującymi częściami. Analizę numeryczną zrealizowano w zakresie sprężysto-plastycznym. W modelu materiału przyjęto nieliniową charakterystykę opisującą stop aluminium. Analizowano wpływ geometrii i warunków brzegowych na pola naprężeń i odkształceń w próbce nitowanej. Badano rozkład naprężeń w przekroju poprzecznym próbki, odkształcenia plastyczne wokół otworu oraz rozwój pola odkształceń plastycznych w trakcie próby statycznego rozciągania. Wyniki symulacji dla analizowanego złącza zakładkowego porównano z wynikami analizy rozciąganej próbki z otworem swobodnym. Model do obliczeń wygenerowano w programie PATRAN. Obliczenia wykonano przy pomocy programów MD NASTRAN oraz MSC.MARC.

EN

The riveted joints are critical places in the aircraft structure with regard to secondary bending, stress concentrations and plastic strain. Analysis of aircraft structures, in it riveted joints requires a local-global approach to numerical modelling. The shell-beam model of the riveted lap joint consisting of two aluminium sheet with six rivets is presented. The rivet is described as a beam element. The contact with friction is defined between the collaborating parts of the joint. Numerical calculation is carried out in elastic-plastic range. The nonlinear stress-strain curve, describing material model of aluminium alloy, is taken into consideration. The influence of the specimen geometry and boundary conditions on strain and stress fields in the riveted joint is studied. Stress distribution in the crosswise sections of the specimen, plastic deformations around a rivet hole and evolution of plastic strain fields during tensile loading are analysed. The results of simulation of tensile loaded lap riveted joint are compared with the results for specimen with open hole. The finite element models are made with Patran. The calculations are preformed using NASTRAN and MARC codes.

3

Explosive charge impact on the openwork steel shield

100%

Sławiński G. , Świerczewski M.

Journal of KONES

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2016

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tom Vol. 23, No. 3

481--487

EN

The article presents the issue of increasing the passive safety of soldiers in a military vehicle, which is subject to loads resulting from an explosion IED or mine. Traditional methods of increasing security involve the application of additional layers, which are made using materials with high density. This approach contributes to the reduction of mobility and efficiency of a vehicle on the battlefield. For these reasons, it is necessary to search for a new structural design, which will benefit from a solution, which will not worsen the driving parameters of a vehicle in combat. Therefore, we propose a novel solution of openwork panel with dividers. The effectiveness of the system will be checked by verified on the bench traverse. The blast shock wave will be induced by detonation of HE charge at the central point over 430 mm from the top surface of the range stand. Experimental test will be used to validate the numerical model. After positive validation and verification, numerical model it can be used for other blast conditions or optimize protective shield. The problem considered in the study was solved numerically with the FEM using the following CAD-CAE systems: CATIA (to prepare a surface model), HyperMesh (division into finite elements), LS-Dyna (a solver), LS-PrePost (pre and post processor).

4

Modelling and numerical analysis of explosion under the wheel of light armoured military vehicle

100%

Świerczewski M. , Sławiński G.

Engineering Transactions

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2017

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tom Vol. 65, iss. 4

587--599

EN

The article presents a method for numerical modelling of a blast shock effect on unsprung parts of the military vehicle suspension. An explosive charge during the tests was placed under a vehicle wheel according to STANAG 4569 requirements. The mass of the charge is 10 kg of TNT, which corresponds to the highest level of safety – 4a. During the research, there was also tested an influence of application of Run Flat in the Tyre-Run Flat-Rim system on the propagation of a shock wave under the vehicle chassis. A model and numerical calculations were carried out with the use of the following programs: CATIA, HyperMesh, LS-PrePost, LS-Dyna. To describe an effect of a pressure wave on the structure, ALE approach was applied, which allowed mapping such processes as: detonation, wave propagation, interaction with a structure and ORFF system response.

5

Wstępna analiza numeryczna oddziaływania odłamka i wybuchu IED na płytę stalową

80%

Barnat W. , Panowicz R. , Niezgoda T. , Sławiński G.

Modelowanie Inżynierskie

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2011

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tom T. 11, nr 42

37-43

PL

W pracy opisano wstępne wyniki symulacji numerycznej zjawiska sprzężonego oddziaływania wybuchu i odłamka na płytę stalową. Kształt odłamka przyjęto na podstawie STANAGu 4569. Do przeprowadzenia symulacji wykorzystano metodę elementów skończonych (MES) zaimplementowaną w programie MSC Dytran. Obliczenia numeryczne wykonano w opcji explicite na wieloprocesorowym klasterze obliczeniowym. Niezbędne do budowy modelu dane materiałowe zaczerpnięto z dostępnej literatury.

EN

Impact resistance of material structure and standardizations issues, concerning armoured objects, are discussed in many articles. Recent military conflicts show that the Improvised Explosive Devices are the most dangerous threats to the soldiers. In this article an analysis of simultaneous impact of steel ball and blast wave on an armour plate is presented. The simulation was conducted using FE method implemented in MSC Dytran. As a result, stress maps, displacement and energy graphs were obtained. The data was later used to adjust the numerical model. Such an analysis is important in the modern armour design process as it allows investigation in many cases without excessive costs.

6

Modelowanie i analiza MES technologicznego procesu nitowania pokryć lotniczych

80%

Szymczyk E. , Jachimowicz J. , Sławiński G. , Derewońko A.

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2008

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tom R. 49/2, nr 4-5

88-94

PL

Połączenia nitowe są nadał szeroko stosowane w przemyśle lotniczym. O stanie połączenia decyduje nie tylko obciążenie eksploatacyjne, ale również sposób jego wykonania. Dlatego należy uwzględnić wypływ czynników konstrukcyjnych, materiałowych a przede wszystkim technologicznych na wytrzymałość połączenia. Przedstawiono trzy warianty symulacji zakuwania na prasie nitu grzybkowego w celu wyznaczenia rozkładów oraz wartości naprężeń wstępnych w połączeniu nitowym, a tym sann oceny stopnia wypełnienia otworu nitowego.

EN

The riveted joints are still commonly used in aircraft structures. Manufacturing process as well as service load has an important influence on the strength of the joint The effect of the design, material and rivet manufacturing factors on fatigue performance of the riveted joint should be considered. Three cases of simulation of the riveting process are presented in the paper. The stress and strain states around the rivet hole after riveting are compared.

7

Wpływ luzów geometrycznych na stan naprężenia w otoczeniu nitu grzybkowego

80%

Sławiński G. , Szymczyk E. , Niezgoda T. , Jachimowicz J.

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2010

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tom R. 51, nr 3

29-32

PL

W artykuleprzedstawiono wyniki symulacji numerycznych dotyczących wpływu wybranych imperfekcji geometrycznych naprężenia w otoczeniu nitu. W trakcie spęczania nitu do łączonych blach wprowadzane są naprężenia własne, których przekracza granicę plastyczności. Zjawisko to wpływa na poprawę trwałości zmęczeniowej połączenia. Jednak można się spodziewać, że niedokładności wykonania mogą wpłynąć na pogorszenie wytrzymałości połączenia nitowego.

EN

This paper deals with the numerical FE simulation of the geometrical imperfections influence on the residual stress fields around the rived hole. The residual stress state occurs in the rivet hole after the riveting process exceeds the yieldstress level. It has significant influence on the fatigue life improvement of aircraft structures, however, some geometrical imperfections can reduce the strength of the riveted joint.

8

Numerical study on the modification effect of the seat load acting on a soldier during the blast wave derived from IED explosion

80%

Sławiński G. , Dziewulski P. , Niezgoda T. , Malesa P.

Journal of KONES

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2016

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tom Vol. 23, No. 3

465--472

EN

The structure of a vehicle located in the explosion area of an anti-vehicle mine or an IED is subject to a strong impact of a blast wave. The explosion of a mine produces a blast wave that travels in all directions at a speed greater than the speed of sound. The level of risk to the crew of a military vehicle depends on their distance from the place of detonation, on the vehicle’s design and in particular on the design of the bottom of the hull and on the assembly and type of seats. The article provides the analysis of the impact of a side explosion on the crew of an armoured vehicle. Since the new classified version of the AEP-55 document, which defines the conditions for testing the resistance of military vehicles to explosions affecting their side, is not available, it was assumed in the numerical analysis that the charge weight of the explosive device is 100 kg TNT, placed between the central vehicle axles at the distance of 400 mm from the bottom and 1,000 mm from the lower board. Two cases were analysed: one where the Hybrid III dummy was placed on the reference seat and the other where it was placed on a modified seat. The analysis is conducted using the LS-DYNA explicit code. Only the vehicle’s hull is considered with suspension and the turret is modelled with mass.

9

Numerical Analysis of Material and Manufacturing Factors in Riveted Joints Under the Imperja Project

80%

Szymczyk E. , Bogusz P. , Sławiński G. , Jachimowicz J.

Fatigue of Aircraft Structures

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2012

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tom Iss. 4

100--113

EN

The aim of the project was to improve fatigue performance of riveted joints in airframes. Fatigue strength of a joint depends on structural, material and manufacturing factors. The project involved numerical and experimental analysis of material factors and manufacturing imperfections. The paper deals with the analysis of material structure and properties by means of the optical and SE methods. Static monotonic tests for sheet and rivet materials were carried out. ARAMIS optical system was used for the study of deformation and strain fields in the material during loading. This tool offers the possibility of a non-contact measurement with 3D image correlation methods (digital image correlation, DIC) using high-resolution digital CCD cameras. In ductile materials (such as aluminium alloy), subjected to appropriate loading conditions, voids may form, which grow and coalesce leading to crack formation and potential failure. A micro crack may be initiated at the inclusion particles and then voids grow around it. Experimental studies showed that these processes are strongly influenced by hydrostatic stress (Gurson’s material model). SEM analysis of material structure was carried out after performing static tests. In the paper, the authors present the influence of a material model on the results of numerical simulation of the tensile loaded samples with open and riveted holes. The application of Gurson’s material model allows observation of crack growth in the sample cross-section and determination of the sheet rupture as the moment when constraint force decreases to zero (material separation occurs).

10

Wpływ wybranych czynników konstrukcyjnych na rozkład naprężeń w zakładkowym połączeniu nitowym

80%

Szymczyk E. , Sławiński G. , Jachimowicz J. , Derewonko A.

Mechanik

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2010

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tom R. 83, nr 2

115-117

PL

Analizowano wpływ lokalnej zmiany grubości blachy na rozkłady i wartości maksymalnych naprężeń oraz stref naprężeń plastycznych wokół otworów. Wyznaczono również siły przenoszone przez nity oraz blachy w trakcie rozciągania nitowego połączenia zakładkowego.

EN

Discussed are effects of local change of metal sheet thickness on the maximum plastic strain in the material surrounding the holes. The loads as carried over by the rivets and by the metal sheet material in a lap type river joint during tension test are determined.

11

Investigation of human body exposed to blast wave derived from improvised explosive devices

80%

Sławiński G. , Dziewulski P. , Niezgoda T.

Journal of KONES

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2015

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tom Vol. 22, No. 4

287--294

EN

The analysis of contemporary military conflicts shows, that the most dangerous threat for soldiers are Improvised Explosive Devices (IEDs). Blast resistance of military vehicles and structures is broadly discussed in many articles. However, information about human body response to impact loading is hard to find and very general. Both experi-mental trials with dummies and numerical analyses are needed. To design and develop better protection system it is necessary to identify and measure the effects of blast wave impact on crew of military vehicle. This paper presents numerical simulation results of special armoured vehicle subjected to mine threat of 8 and 10 kg of TNT. Possible effects of mine explosion on human body are described. Review of modern-mine and IED countermeasure solutions is presented. The analysis is conducted using LS-DYNA explicit code. Only vehicle’s hull is considered with suspension and turret is modelled using mass. Gravity is taken into account. Numerical model of Hybrid-III dummy is used. Accelerations and forces in tibia, neck and spine were calculated. HIC-36 criterion was also evaluated Different types of possible seat configuration are examined. Results show convergence between explosive size and injury risk.

12

Numerical analysis of the influence of blast wave on human body

80%

Sławiński G. , Niezgoda T. , Barnat W. , Wojtkowski M.

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2013

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tom Vol. 20, No. 3

381--386

EN

Threats for military personnel during combat missions nowadays are of different sources. Further development of methods for neutralization of mines or improvised explosive devices (IED) explosions must be preceded by identification of the impact phenomenon on crew of the military vehicle. Large accelerations cause injury to a person located in the interior of the vehicle and may lead to permanent disability exempting soldiers from the battlefield. Information about overload coming from the explosion of IEDs on humans are difficult to access or not sufficiently detailed. Therefore, the basis for their acquisition is conducting experimental research and modelling. The paper is presents finite element analysis of blast wave effects on a human body simulated by a numerical 50th percentile HYBRID III dummy. Coupled Euler and Lagrange (ALE) formulations are used in the finite element analysis of such problems to accurately represent the detonation phenomenon. Numerical model was developed in LS-PrePost software. All the computational analyses were carried out using an explicit LS-DYNA solver on multiprocessor cluster. Data such as hip and knee moment of inertia, femoral force, and foot acceleration are collected from the numerical dummy, which simulates the occupant’s response. These data are then compared to injury threshold values from various references to assess survivability

13

Energia z głębokich pokładów gorących suchych skał (HDR) do poprawy bezpieczeństwa infrastruktury krytycznej Polski

80%

Niezgoda T. , Miedzińska D. , Sławiński G.

Inżynieria Bezpieczeństwa Obiektów Antropogenicznych

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2018

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tom Nr 3-4

65--69

PL

W artykule przedstawiono zarys technologii wydobycia ciepła z głębokich pokładów gorących suchych skał (HDR – hot dry rocks), możliwości jej implementacji na terenie Polski oraz jej zalety w aspekcie zastosowania do poprawy bezpieczeństwa infrastruktury krytycznej, jak również poprawy bezpieczeństwa energetycznego Polski.

EN

In the paper the scheme of technology of heat recovery from deep beds of hot dry rocks (HDR) and the possibilities of its applications in Poland were presented. Also the advantages of the HDR technology implementation in accordance to critical infrastructure safety improvement as well as for Poland energetic safety increase were shown.

14

Walidacja badań eksperymentalnych zjawiska wybuchu z wykorzystaniem metody elementów skończonych

80%

Malesa P. , Sławiński G. , Bogusz P. , Świerczewski M.

Modelowanie Inżynierskie

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2018

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tom T. 35, nr 66

46--52

PL

W pracy przedstawiono podejście numeryczne do modelowanie zjawiska inicjacji oraz propagacji fali uderzeniowej pochodzącej od wybuchu TNT w aspekcie badań poligonowych. Przedstawiono wyniki analiz numerycznych modeli opracowanych na podstawie badań eksperymentalnych odzwierciedlających warunki badań poligonowych. Symulacje przeprowadzono przy użyciu dwóch algorytmów dostępnych w kodzie obliczeniowym LS-Dyna - podejścia ALE (Arbitrary Lagrangian-Eulerian) oraz funkcji CONWEP. Otrzymane charakterystyki zmiany ciśnienia dla punktów pomiarowych odpowiadających miejscu mocowania czujnika ciśnienia w warunkach poligonowych pozwolą na poprawną walidację badań eksperymentalnych zjawiska wybuchu. Do zrealizowania postawionego zadania wykorzystano oprogramowanie Hypermesh, LS-Prepost oraz LS-Dyna.

EN

The paper presents the results of numerical analyses of models developed based on experimental tests representing the field tests conditions. The paper presents a numerical approach to modelling the phenomenon of initiation and propagation of a wave from TNT explosion in terms of field tests. The simulations were conducted with the use of two algorithms implemented in LS-DYNA code: ALE (Arbitrary Lagrangian-Eulerian) method and CONWEP function. The obtained characteristics of pressure change for measurement points corresponding to the location of pressure sensor fixture in the field tests conditions will allow accurate validation of experimental tests of an explosion phenomenon. Hypermesh programme was applied to accomplish the given task, LS-Prepost to develop a model and analyses the results and LS-Dyna as a solver for conducting the calculations.

15

Influence of the volume fraction of the carbonyl iron particles on the mechanical properties of the magnetorheological elastomers

80%

Sławiński G. , Niezgoda T. , Miedzińska D. , Gieleta R.

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tom Vol. 17, No. 3

401-406

EN

Magnetorheological materials belong to the group of the so called intelligent materials. Their rheological properties can be changed in a large range using an external magnetic field. That is why they fmd ever growing application in modern technical equipment, among others in controlled dampers, clutches, sensors etc. In the paper, a numerical strength analysis of a magnetorheological material was presented. The influence of the volume fraction of carbonyl iron particles (the share of the carbonyl iron particles varied from 1.5 to 33.0 vol. %.) on the mechanical properties of the material were investigated, in particular on the Young's modulus variation. Experimental tests were carried out for specimens made of pure PU 70/30 elastomer with iron particles. They induded uniaxial compression tests. In the farmer case, specimens were in a shape of a cylinder with a diameter of 20 mm and a height of 25-30 mm. The results of experimental tests carried out in order to determine the parameters necessary to build the numerical model were induded in the paper. In the paper, an algorithm developed for determining the parameters for modelling the structure was presented. A fragment of the structure, containing several particles of iron and some quantity of elastomer, corresponding to the assumed volume fractions, was subjected to numerical analysis.

16

Numerical study of the influence of shape imperfections on residual stress fields in a rivet hole

80%

Sławiński G. , Niezgoda T. , Szymczyk E. , Jachimowicz J.

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tom Vol. 17, No. 2

427-434

EN

The paper deals with the numerical analysis on residua! stress and strain fields in a rivet hole. This stage of study concerns improving of the fatigue performance of riveted joints in an airframe. Riveting, particularly in aviation, is a traditional but still commonly used method of joining sheet metal components. Aircraft structures are thin-walled ones, with coverings made of thin sheets stiffened by stringers, frames or ribs. Sheets are typically assembled by a multiple rivet or bolt joints. Rivets and bolts are also used to joint sheets and stiffeners. Therefore, fatigue resistance of the aircraft structure depends on tens of thousands or even hundreds of thousands r ivet joints, which are used to build it. The local numerical models of the joint are considered with regard to the aim introduced in the paper. Numerical FE simulations of an upsetting process are carried out using the LS-DYNA code. Three-dimensional numerical models are used to determine the resulting stress and strain fields at the mushroom rivet and around the hole. This type of problem requires the use of contact between the elements assembled and non-linear geometrie and elasto-plastic multilinear materiał models to simulate the behaviour of the rivet and sheets. The influence of shape imperfection on strain and stress states is studied.

17

Numeryczne badania mat energochłonnych jako element zwiększający bezpieczeństwo załogi pojazdu wojskowego

80%

Sławiński G. , Malesa P. , Niezgoda T.

Aktualne Problemy Biomechaniki

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2016

|

tom z. 11

115--120

PL

W pracy zostały przedstawione wyniki modelowania oraz symulacji numerycznych paneli energochłonnych absorbujących energię pochodzącą od wybuchu. Przedstawiono syntetyczny sposób analizy zagadnienia od opracowania geometrii po przygotowanie modelu numerycznego. Wyniki w postaci sił obciążających charakterystyczne punkty pomiarowe manekina Hybryd III 50th w wersji Fast oraz pozostałe charakterystyki przedstawiono w formie wykresów.

EN

This study presents the results of numerical simulations of an energy absorbing panels as an element increasing the safety of the military vehicle crew. The simulations are made by a finite element method in LS-Dyna. A numerical Hybrid III 50th dummy is used to simulate the tibia axial compressive forces and accelerations. Simulations results are compared with literature data to validate the Hybrid III dummy. Forces and accelerations results are presented in the form of a charts.

18

Analiza wpływu technologii nitowania na stan przemieszczeń, odkształceń i naprężeń wokół nitu

80%

Jachimowicz J. , Szymczyk E. , Sławiński G.

Mechanik

|

2008

|

tom R. 81, nr 4

332-337

PL

Przedstawiono wyniki obliczeń numerycznych, które pokazują wpływ czynników technologicznych na proces nitowania.

EN

Presented are the results of numeric calculations to demonstrate the effect of the process features on riveting operation.

19

Analiza wpływu luzów technologicznych na pole naprężeń własnych w otoczeniu nitu stożkowego

80%

Szymczyk E. , Jachimowicz J. , Sławiński G.

Mechanik

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2008

|

tom R. 81, nr 7

629-632

PL

Przedstawiono wyniki symulacji numerycznych procesu zakuwania nitu stożkowego dla różnych wartości średnicy otworu nitowego. Model numeryczny połączenia zweryfikowano jakościowo i ilościowo na podstawie obliczeń analitycznych i badań doświadczalnych.

EN

Presented are the results of numerical simulation exercise of the operation of setting steeple head rivets in various diameter rivet holes. Numerical model of the rivet joints were verified to quality and quantity parameters with reference to analytical calculations and practical tests.

20

Optimization of two-component armour

80%

Kędzierski P. , Morka A. , Sławiński G. , Niezgoda T.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2015

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tom Vol. 63, nr 1

173–-179

EN

The paper presents research on optimization of two-layer armour subjected to the normal impact of the 7.62x54 B32 armour piercing (AP) projectile. There were analysed two cases in which alumina Al2O3 was supported by aluminium alloy AA2024-T3 or armour steel Armox 500T. The thicknesses of layers were determined to minimize the panel areal density whilst satisfying the constraint, which was the maximum projectile velocity after panel perforation. The problem was solved through the utilization of LS-DYNA, LS-OPT and HyperMorph engineering software. The axisymmetric model was applied to the calculation in order to provide sufficient discretization. The response of the aluminium alloy, armour steel and projectile material was described with the Johnson-Cook model, while the one of the alumina with the Johnson-Holmquist model. The study resulted in the development of a panel optimization methodology, which allows the layer thicknesses of the panel with minimum areal density to be determined. The optimization process demonstrated that the areal density of the lightest panel is 71.07 and 71.82 kg/m2 for Al2O3-Armox 500T and Al2O3-AA2024-T3, respectively. The results of optimization process were confirmed during the experimental investigation.