Wyniki wyszukiwania - BazTech

1

Hydropneumatic suspension testing of a wheeled armoured personnel carrier

Hryciów Zdzisław, Rybak Piotr, Wojciechowski Michał, Wachowiak Przemysław, Kalicki Bartosz

Eksploatacja i Niezawodność

|

2023

|

Vol. 25, no. 2

art. no. 162497

EN

The purpose of this study was to determine the effect of gas pressure and temperature on the spring characteristic of a HP strut used in a wheeled armoured personnel carrier. The research was performed based on a simulation model. Data to validate the model were obtained during experimental tests. The results indicate, among other things, that the friction generated in the seals is an important source of resistance force. Comparison of the simulation results with the measured characteristics indicates a proper modelling of the strut operation. Simulation studies have indicated that it is easy to modify the required suspension parameters by adjusting the initial gas pressure. A linear effect of pressure on static deflection can be assumed. Temperature has a strong influence on the spring characteristic. When it changes, significant changes in vehicle height are observed due to the lack of a compensation system. The temperature changes are not only due to changes in ambient temperature, but also by intense heating of the HP struts caused by the vehicle moving over rough terrain.

2

Assessment of the impact of wear and tear of rubber elements in tracked mechanism on the dynamic loads of high-speed tracked vehicles

Rybak Piotr, Hryciów Zdzisław, Michałowski Bogusław, Wiśniewski Andrzej

Acta Mechanica et Automatica

|

2023

|

Vol. 17, no. 1

85--94

EN

The operation of high-speed tracked vehicles takes place in difficult terrain conditions. Hence, to obtain a high operational relia-bility, the design or modernisation process must be precise and should consider even the slightest details. The article presents issues re-lated to the problem of formulating vehicle models using partial models of flexible elements used in tracked mechanisms. Changes occur-ring in the shape and properties of elements such as track pads and roadwheel bandages as a consequence of operating conditions are presented. These changes are reflected in the presented elastic–damping characteristics of components of the crawler mechanism. Nu-merical studies have shown that deterioration of chassis suspension components after a significant mileage may increase dynamic loads (forces) acting on the running gear. Increased forces in the running gear naturally result in increased stresses in the road surface on which the vehicle is travelling, which can pose a danger (or excessive wear and tear) to road infrastructure components such as culverts, bridges and viaducts. In the literature, model tests of objects are carried out on models that represent new vehicles, and the characteristics of the adopted elements correspond to elements not affected by the process and operating conditions. Its influence should not be ignored in the design, testing and running of a special vehicle. The tracked mechanism, as running gear, is designed for special high-speed vehicles for off-road and off-road driving. Its design ensures high off-road traversability. The dynamic loads originating from off-road driving are super-imposed on those generated by the engine, drive train and interaction of the tracks with the roadwheels, sprocket, idler and supporting tracks return rollers.

3

The influence of temperature on the damping characteristic of hydraulic shock absorbers

Hryciów Zdzisław, Rybak Piotr, Gieleta Roman

Eksploatacja i Niezawodność

|

2021

|

Vol. 23, no. 2

346--351

EN

This paper presents the results of bench-tests and calculations assessing the influence of temperature on the performance of a two-pipe hydraulic shock absorber. The shock absorber prepared for the tests was cooled with dry ice to a temperature corresponding to that associated with the average winter conditions in a temperate climate. The temperature range of the shock absorber during testing was ensured via equipping it with a thermocouple and monitoring it with a thermal imaging camera. During testing, the shock absorber was subjected to kinematic forces of a selected frequency with two different, fixed displacement amplitudes. The results of the tests showed a direct correlation between the decrease of component resistance at lower temperatures. The rate of change in resistance was higher at lower temperatures. It was also found that the energy dissipated in one shock cycle decreased linearly with an increasing temperature. Finally, a method for determining the ideal use temperature of the shock absorber for the assumed operating conditions was also presented.

4

Assessment of the effect of passenger car wheel unbalance on driving comfort

Hryciów Zdzisław, Wiśniewski Andrzej, Rybak Piotr, Tarnożek Tomasz

Archiwum Motoryzacji

|

2021

|

Vol. 94, nr 4

61--71

EN

This paper presents the results of experimental investigations of the effects of car wheel unbalance on driving safety and comfort. Basic information about types of wheel unbalance, their causes, and effects are included. The test subject was a BMW 3 Series car with rear-wheel drive. A specific unbalance was introduced on the front steered wheels. The vehicle was driven in a straight line on an asphalt road in good condition at speeds between 70 km/h and 140 km/h. During the test runs, acceleration waveforms were recorded from sensors placed on the lower control arm, driver's seat, and steering wheel. The vibration level of the unbalanced wheel increases with the driving speed and with the increase in unbalance. The highest increase in vibration amplitude occurred on the steering wheel at speeds between 100 km/h and 120 km/h. These vibrations have a direct effect on the driver. This is evidenced by negative driver perceptions such as fatigue and driving discomfort. This was also confirmed by the calculated vibration exposure levels. Driving with unbalanced wheels accelerates wear on the tyres, steering, drive, and suspension components of the vehicle.

5

Analiza wpływu modernizacji na własności czołgu

Rybak Piotr, Wiśniewski Andrzej

Journal of KONBiN

|

2020

|

Vol. 50, iss. 2

219--230

PL

Jakość funkcjonowania gąsienicowego wozu bojowego można ocenić na podstawie parametrów jego bojowo-technicznej charakterystyki, którą formułowano na etapie projektowania. Jednakże upływ czasu, nowe i zmieniające się w czasie zagrożenia, dynamika działań, postęp techniczny i technologiczny weryfikują ich skuteczność oraz odporność. W efekcie pojawia się, dla sprostania wymaganiom aktualnym i przyszłym, konieczność modernizacji. Jej głównym celem jest uzyskanie, poprzez odpowiednie zabiegi, przewagi nad pojazdami bojowymi potencjalnego przeciwnika. W pracy podjęto próbę analizy modernizacji na wybrane właściwości czołgów, najbardziej zaawansowanych środków walki wojsk lądowych. Analizę przeprowadzono w aspekcie wpływu zwiększenia masy bojowej na istotne elementy czołgu.

EN

Functional quality of caterpillar fighting vehicles can be assessed upon its original project design and technical characteristics. However, lapse of time, technical and technological progress, battlefield dynamics, new and evolving threats can negatively verify both offensive and defensive effectiveness of such vehicles. As a result, appears need of modernization addressing new threats and requirements. Main goal of modernization is to achieve advantage over potential enemy fighting vehicles. This work is an attempt to analyse possible development patches and despite technological and materials progress inseparable increase of the vehicle's combat weight on operating capabilities of such vehicles.

6

Stability of wheeled armoured personnel carrier firing sideways

Wiśniewski Andrzej, Rybak Piotr

Journal of KONES

|

2019

|

Vol. 26, No. 2

175--180

EN

One of the most important and commonly used means of transport in the armed forces of various countries is wheeled armoured personnel carriers. After proper preparation, beside transport tasks, they can carry out special tasks, as part of regular and irregular activities within purpose of supporting actions of troops. This paper presents preliminary results of numerical research of wheeled armoured personnel carrier with 8x8-drive system. The effect of impact of large calibre cannon (120 mm) with reduced recoil force on transporter behaviour was investigated. The research object model consists of shell, solid and discrete elements. The research was carried out in the LS-DYNA software. Considered variant applies to sideways firing (to the left of the vehicle) for cannon elevation angle 16 deg. Numerical model of standing still on the flat ground wheeled armoured personnel carrier was preloaded with the gravitational force. The results of post-firing vehicle behaviour including angular displacement of the hull, dynamic deflections of the suspensions and impact on the stability of the wheeled vehicle were evaluated.

7

Distribution of masses and presses on axles and wheels and vehicles’ properties

Rybak Piotr, Wiśniewski Andrzej

Journal of KONES

|

2019

|

Vol. 26, No. 1

141--146

EN

One of the most important parameters affecting traction properties as well as driving safety, especially with regard to vehicles with special purpose, is the distribution of wheel and axle loads on the ground. This issue should be taken into account during the process of creating new vehicles as well as during the modernization process. In the first case, it is quite simple because the mass distribution is shaped already in the design phase. In the second case, the problem is more complex, because with modernization solutions we enter an already existing structure. Modernization basically assumes improving the performance and capabilities of the vehicle with possibly small changes in its base structure. Thus, it imposes important boundary conditions. The article presents the methodology of measurement and selected results of measurements of mass distribution as well as wheel and axle loads of selected motor vehicles during their advanced modernization (STAR 266 cars to the version STAR 266M2 and Honker 2000 to the version Honker M-AX). Modernizations carried out by Autobox Innovations Ltd. Lim. Par are mainly focused on increasing the traction of vehicles, traffic safety, and driving comfort. Measurements were made at the above-mentioned company.