Papers by Author: Stanislav Rolc

Abstract: The work is focused on mechanical and ballistic properties of textile materials most used in personal protection (ballistic vests, helmets), i.e. aramid fabrics. Physical and mechanical properties such as Young’s modulus, maximum strength before rupture, tensile strength, elongation at rupture and combustion velocity were measured. Ballistic resistance of sets of selected fabrics was tested. Ballistic tests were focused on protection level TBO-2/CZ according to ČSN 395360. Differences in physical and mechanical properties of commercial fabrics used as inner soft armour and fabrics used for trauma effect reduction were observed. It was found out that different order and combination of different types of textile fabrics influence significantly the ballistic efficiency of fabric sets.

Abstract: The ballistic performance of ceramic materials was investigated. Various types of ceramic-metals and ceramic-laminate composites were prepared. Their ballistic resistances against AP small arms ammunition of protection level 2 and 3 according to NATO Standardization Agreement STANAG 4569 were investigated. For the ballistic performance assessment V50 test method was used. From economical, technological, and ballistic point of view as optimal solution sandwich structure consisting of alumina front-face layer and aramid or duralumin backing layer was found.

Abstract: The technology of explosive welding (EXW) was used for development of metallic multilayer ballistic resistant materials. Explosive cladded two or multilayer materials serve as final product or as semi-finished product for further processing, e.g. rolling. The objective is to create material with sufficient ballistic resistance at relatively small thickness of the resulting multilayer structure. Under retaining the weight of armoured vehicle its ballistic resistance can be increased or, under retaining its existing ballistic resistance the weight can be reduced. Resulting material should be producible of commercially available metallic materials using common technologies, especially the technology of roll welding (ROW). For the primary tests it is possible to model the resulting structure by means of EXW and some its properties can be verified in the initial stage of research of the multilayer structure (e.g. tests of heat processing, verification of diffusion processes, behaviour under various types of load, verification of ballistic resistance and other technological tests). Subsequently, production can start of large semi-finished products by means of ROW technology. Effective preparation is possible of the samples of multilayer materials by means of EXW technology in various material combinations - armour steel, tool steel and interlayer based on nickel, nickel alloys etc.

Abstract: This paper deals with the dynamic response of clamped plate to the loading following from the detonation of buried explosive charge. The cylindrical explosive charges of 8 kg mass has been considered. The numerical analysis is carried out using the LS DYNA finite element code. Numerical results exhibit reasonable agreement with results of controlled explosion experiments. The study is oriented mainly on the effects of structure representations (solids or shells) and of computational mesh size on evaluation of the structure response.