Jiri Pachman

Detonation Characteristics of Plastic Explosives Based on Attractive Nitramines with Polyisobutylene and Poly(methyl methacrylate) Binders

Four highly brisant nitramines, RDX (1,3,5-trinitro-1,3,5-triazinane), HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocane), BCHMX (cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d]imidazole), and ϵ-HNIW (ϵ-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane), were studied as extruded plastic explosives bonded by two plastic matrices based on polyisobutylene (C4 matrix) and poly-methylmethacrylate (plasticized by dioctyl-adipate) binders. The detonation velocities, D, were measured experimentally. Detonation parameters were also calculated by means of the Kamlet and Jacobs method and CHEETAH and EXPLO5 codes. These detonation parameters showed that plastic-bonded explosives (PBXs) based on BCHMX are more powerful explosives than those based on RDX. The Urizar coefficient for poly(methyl methacrylate) binder was also calculated.

The structural response of a reinforced concrete specimen subjected to adjacent blast loading

The paper presents the results of the field tests of FRC and reinforced concrete specimens which were performed in cooperation with the Czech Army corps in the military training area Boletice. The tests were performed using real scale reinforced concrete precast slabs (6×1.5×0.3 m) with varying fibre content, fibre type, fibre strength and concrete strength class and 25 kg of TNT charges placed at a distance from the slab for better simulation of real in-situ conditions. The slabs were recorded using a high speed framing camera during the blast loading. The instrumentation enabled us to study the propagation of the blast shock wave through the material, propagation of the cracks on the soffit of the specimen and the final collapse of the middle part of the slab exposed to blast loading. The sequence of the structural behaviour is documented in detail and verified by numerical modelling using the LS-DYNA solver.

Testing optical tracking of blast wave position for determination of its overpressure

The photogrammetry is a method for determination of physical parameters behind the primary shock wave by optical methods. This paper is focused on determination of overpressure by this method and its comparison with pressure measurement by pencil probes. For the tracking of shock wave front a subtraction of consecutive frames captured by the high-speed camera was used.

Ring plane wave generator

Experiments with a simple plane wave generator consisting of two cylindrical explosive charges and a metal ring are presented in this work. Detonation front curvature emerging from the second charge is measured using high-speed camera and Optimex fiber based device. The results are compared with LS-DYNA simulations.