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.
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.
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 90's, 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.
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 . Examples of model test results were compared with experimental test results obtained on the test track.
Modern wheeled armoured vehicles are constructed as multipurpose. Universal construction of vehicle is achieved in two separate ways: as specialized versions of vase model or by using exchangeable mission-modules. Realization of various tasks requires different equipment; ensure adequate level of protection and firepower. Increase of protection level, implementation of weapon systems, characterized by high firepower despite technological advancement in this field affect vehicles weight increase and therefore, it also affects requirements for other vehicle systems. Ensuring high mobility requires use of high power, turbocharged diesel engines, hydro mechanical transmission, hydro pneumatics suspension, possibility of clearance adjustment, use of central wheel pumping system enabling tire pressure change according to the surface on witch vehicle runs. This study gathers and compares characteristics of selected wheeled armoured personnel carriers and determines possible directions of development for future wheeled vehicles.
The extortions that result in the vibrations of a hull of the combat vehicle have an impact on the tracked combat vehicle during the off-road driving. They may have a negative impact on the crew, internal equipment, shooting accuracy. A level of the hull loads depends on quality of the suspension system, which main responsibility consists in minimising an amplitude of the vibrations. Therefore, it is necessary both to improve a structure of the suspension system, and its components, as well as their optimisation.
The tests of the driving smoothness of the vehicle and quality of the suspension elements can be realised both within a frame of the model tests and while driving in the real conditions. The assessment criteria of the driving smoothness are directly related to the negative influence of the vibrations to the human body. The suspension quality should be assumed both upon an execution of the vehicle prototype, and during the design or modernisation phase. It results both in reducing the time, and minimisation of the costs and risk related to the structure development. The model tests enable to evaluate the driving smoothness and comfort prior to an execution of the prototype. The tests on the test tracks in the final phase of the development are carried out in order to evaluate the driving smoothness.