W. Borkowski

The Researches of Effectiveness of Road Restraint Systems

The Researches of Effectiveness of Road Restraint Systems The work describes model and experimental tests on the road restraint systems with particular attention to vehicle collisions with a concrete protective barrier. Vehicle and protective barrier crash tests include the experiment results in three basic fields: intensity of influence of the collision effects on vehicle passengers, collision impact on a vehicle and the road restraint system. It presents a test track concept as well as criteria for performing and evaluating the crash tests with a passenger vehicle and a safety barrier. The experimental tests were performed according to the test methodology recommended by the standard [2]. Examples of model test results were compared with experimental test results obtained on the test track. Badania skuteczności drogowych systemów zabezpieczających W pracy opisano badania modelowe i eksperymentalne drogowych systemów zabezpieczających ze szczególnym uwzględnieniem zderzeń pojazdu, ze sztywną barierą zabezpieczającą. Badania zderzeniowe pojazdu z barierą ochronną obejmują wyniki eksperymentu w trzech podstawowych obszarach: intensywność oddziaływania skutków zderzenia na osoby znajdujące się w pojeśdzie, skutki oddziaływania zderzenia na pojazd oraz odkształcenie drogowego sytemu zabezpieczającego. Przedstawiono koncepcję toru badawczego oraz kryteria przeprowadzenia i oceny próby zderzeniowej samochodu osobowego z betonową barierą zabezpieczającą. Badania eksperymentalne zrealizowano zgodnie z metodyką badań zalecaną przez normę [2]. Przykładowe wyniki badań modelowych porównano z wynikami badań eksperymentalnymi uzyskanymi na poligonowym torze badawczym.

Numerical research on dynamic loads of wheeled armoured personnel carrier during overcoming terrain obstacles

Paper presents the results of numerical research on the influence of the movement conditions (velocity and various types and parameters of obstacles) on the level of dynamic loads of the body shell and the vehicle crew of the basic version of Wheeled Armoured Personnel Carrier (Wheeled APC) ROSOMAK. The research work was aimed at analysis of the dynamic loads resulting from the overcoming various terrain obstacles. Kinematic constraints acting on suspension used during tests were random and deterministic, e.g. sine, cosine, triangle as well as mixed, imitating fallen tree trunk on smooth surface. Simulations were carried out with the genuine proprietary software for numerical analysis of dynamics of multi-axis vehicles equipped with independent suspension. The paper consists description of the mathematical model of multi-axis vehicle, deterministic and random generated inputs and range of performed tests. Time courses of displacement, velocity, vertical and angular (longitudinal and transverse) accelerations were determined for chosen parts of vehicle. Paper also contains time courses of deflection for every suspension wheel and dynamical reactions of the ground as well as selected time charts and cumulative statistics. Finally paper presents conclusions formulated about dynamic loads of APC ROSOMAK depending on parameters and types of obstacles and vehicle velocity.

Combat Vehicle Dynamic Load Tests in the Aspect of the Operation Safety

Combat Vehicle Dynamic Load Tests in the Aspect of the Operation Safety The scientific team, working in the Mechanical Vehicle and Transport Institute of the Mechanical Department of the Military Technical Academy since the 90s, has been dealing with the analysis of dynamic loads of combat vehicles (tanks, infantry combat vehicles and wheeled armoured carriers). The work presents the combat vehicle tasks and operation tasks and conditions. Possible threats and possible effects of their influence were described on the basis of available information. The results of own model and experimental tests of dynamic loads affecting the aforementioned vehicles were presented. Selected analysis results were presented in a form of characteristics, diagrams and tables. Due to a type of analysed vehicles, the results are of qualitative nature rather than the quantitative one. Badanie obciążeń dynamicznych wozów bojowych w aspekcie bezpieczeństwa ich użytkowania Pracujący, w Instytucie Pojazdów Mechanicznych i Transportu Wydziału Mechanicznego WAT, od początku lat 90-tych zespół naukowy zajmuje się badaniem oraz analizą obciążeń dynamicznych wozów bojowych (czołgów, bojowych wozów piechoty oraz kołowych transporterów opancerzonych). W pracy przedstawiono zadania oraz warunki eksploatacji wozów bojowych. Opisano potencjalne zagrożenia oraz, na podstawie dostępnych informacji, ewentualne skutki ich oddziaływania. Zamieszczono wyniki własnych badań modelowych oraz eksperymentalnych obciążeń dynamicznych działających na w/w pojazdy. Wybrane rezultaty analiz zaprezentowano w postaci charakterystyk, wykresów i tabel. Z uwagi na rodzaj analizowanych pojazdów rezultaty mają głównie charakter jakościowy a nie ilościowy.

Influence of the shape of the explosive charge on blast profile

When an explosive charge is fired, the nature and mass of the explosive are the only parameters of importance usually considered. The shape however, also plays a major role in the effect of an explosive charge. Knowledge of shape effect can be important before the use of the explosive (in order to create a maximum effect with a given mass of explosive), or in post-explosion damage assessment. The shape effect however is only significant within a certain range from the charge. At longer distance, the produced blast wave tends to be spherical. The shock wave parameters studied in this work are the peak overpressure and the first positive impulse. A series of numerical test has been performed in order to determine the range of influence of the charge shape. Different locations of initiation were compared. A hemispherical charge was point detonated at its centre whereas a cylindrical shape was detonated at the centre of an upper or lower plane. Numerical simulations of near field burst were conducted using LS-DYNA software. During numerical tests a pressure fields were determined for different shapes of explosive charges as well as the pressure waveforms at points located 1000 mm from a centre. Additionally, reference pressure history curves from LOAD_BLAST_ENHANCED procedure were calculated.

Research on the effectiveness of the innovative protective structure for vehicles

This article presents results of the research on developed innovative protective structure for vehicles. The fundamental objective of executed work was to check the correctness of assumed assumptions, shape and geometry of the solution and configuration of components that affect the protective effectiveness during the impact of the explosive. In order to reach that goal, both model tests and experimental tests were carried out. The experimental tests were carried out on the real object. Significant information about the level, directions and nature of affecting dynamic loads were obtained as well as information about their impact on particular structure elements. The MES numerical model of the research object has been developed in LS-Dyna system. Special emphasis was placed on the mapping of complex geometry, configuration of components and their interactions. Test calculations were carried out and then the resistance calculations were made. As a load, generating post-explosion impact wave, the load imposed by normative requirements concerning the way of explosive arrangement as well as the shape and weight. The analysis of obtained results of the experimental and numerical tests allows for high evaluation of effectiveness of proposed solution.

The research on dynamic loads and traction properties of military vehicles in the aspect of improvement of their structures

Since the beginning of the 90’s, a scientific team in the Motor Vehicle and Transport Institute of the Mechanical Department in the Military University of Technology, has been involved in the model and experimental tests of the existing structures of the military vehicles (tanks, combat infantry vehicles and wheeled armoured carriers) in the aspect of their modernization. A part of works is related to the military vehicles included in the army’s equipment and the other parts are related to newly designed vehicles. In both cases issues related to the behaviour of selected assemblies and the whole vehicle, structure during threats posed by the reality of contemporary battlefield or armed symmetric or asymmetric conflicts are analysed. Selected effects of the tests and analyses will be presented mostly within the qualitative scope due to the data sensitivity. Contemporary design of military vehicles requires involvement of various research methods and specialized calculation software. The results obtained during performed various experimental tests make a valuable basis for verification of numerical models used in design process and multi-option simulation calculations.

Mathematical model of stabilising and tracking control system in main battle tank

The T-72 battle tank (and its’ derivative PT-91 Twardy) are equipped with 2E28M two-axis stabilisation system and monoaxially (in elevation) stabilised gunner’s sight system. The stabilisation system compensates the velocities of the vehicle. The stabilisation system automatically maintains a position of the gun at a fixed bearing in space. In spite of any motion of the vehicle in roll (LK-rotation round axis yK), in pitch (. K-rotation round axis xK) or in yaw (B K-rotation round axis zK), the tank gun stabiliser minimises the effects of vehicle motion on the main armament of the tank under typical conditions of tank operation over rough ground (see Fig. 1) [1, 2, 4, 7, 14, 21, 25]. The gun is rotated in pitch (. A) relative to the turret by an elevation drive system. A hydraulic servo-motor (actuator), fixed to the gun and turret drives the gun (see Fig. 2) [3, 10, 19]. The turret is rotated in yaw (B W) relative to the hull by an azimuth drive system. A hydraulic servo-motor, fixed to the hull drives the turret. The power for the drive is taken from the onboard 24V system. The power is taken from the generator buffered over a set of batteries. It is fed to the electric motor. This electric motor is turn drives a pump. The electric power is thus converted into hydraulic power. The flow of hydraulic fluid through to the drive unit is controlled by a servo valve. An electronic control unit compares the actual speed of the drive with the speed specified by the gunner and regulates the valve setting accordingly to compensate for any discrepancy between the two (the advantage of such a servo control lies in the precision that it affords, its disadvantage is the loss of power at the servo valve, The tank gun stabiliser is an electro-hydraulic control system which makes possible aiming at a target, tracking of a target and stabilise of a given gun angular position. The two-axial stabiliser consists of two separate control systems to stabilise the gun in elevation and the turret (with gun) in azimuth. The aim of researches was to identify all functional blocks of tank gun elevation stabiliser 2E28M (installed in tanks T-72 and PT-91 Twardy) in order to build mathematical model of the system. After detailed analysis of construction and work principles, schematic of 2E28M hydro-mechanical powered mounting, showing number of energy conversion were worked out. Stabiliser has been divided into appropriate functional parts and functional scheme of investigated system were build. Afterwards, static and dynamic characteristics of functional parts of the system were determined. On the basis of obtained characteristics and based on the knowledge about the system feedbacks, structural scheme and mathematical model of foregoing stabiliser were derived. On the basis of the mathematical model, the algorithm and the computer program were worked out. Making use of the Matlab-Simulink program, one worked-up the scheme for numerical computation. The mathematical model and its numerical implementation have been experimentally verified.

STUDIES ON THE EFFECTIVENESS OF THE INNOVATIVE ROAD SAFETY SYSTEM

The paper evaluates the effectiveness of the innovative road safety system equipped with prototype component segments composed of a body made of a plastic filled with reinforced concrete. Main advantages of the new safety barrier include increased resistance to corrosion as well as easy transport and assembly directly on a road section being secured. Model tests were performed on a car of 900 kg weight allowing for carrying out the TB11 tests according to the EN 1317-2 standard. LS-DYNA software was applied for modelling, using the finite element method. The work presents the numerical test results, trajectory of vehicle movement after collision as well as the concrete barrier displacement. It also includes examples of stress in steel bars and joint coupling. Detailed assessing of simulation test results were made on the basis of ASI, THIV and PHD index. They were calculated on the basis of velocity and acceleration courses of selected car bodywork points. Numerical test results confirm the fact that this system meets the normative requirements. They allow for qualifying that system for B impact severity level and W4 working width. The results presented in the paper make the initial stage of the study and further calculations will be oriented towards a possibility of meeting the requirements for higher restraint levels.