Two devices intended for copper cylindrical liner gasdynamic acceleration to velocities of 5–7 km/s using the chemicals explosion energy have been investigated. It has been demonstrated that the acceleration of quasi-isentropically and isentropically loaded liners under the conditions of high-level dynamics, symmetry of deposition, and suppression of shock-induced dusting is feasible.
In the development of special explosion-proof chambers that must meet strict requirements for strength reliability, an important issue is the choice of the material of the load-bearing shell subjected to pulsed (dynamic and shock-wave) loads. As a rule, these structures are made from industrial low-alloy steel pipes of various standard sizes. This always raises the question of choosing the steel grade, especially at the stage of design-basis justification of their explosion resistance, since the dynamic strength characteristics of the pipe material are generally unknown. This paper is the first to present the results of analysis of the static, dynamic, and shock-wave compressive and tensile strengths of 17G1S, 09G2S, 10G2FBYu, and K60 strength class pipe steels. In addition, comparative data are given on the explosion resistance of pipes of 09G2S and 10G2FBYu steels at a strain rate of (2-5)· 10^2 s ^-1 .
Two devices intended for copper cylindrical liner gasdynamic acceleration to velocities of 5–7 km/s using the chemicals explosion energy have been investigated. It has been demonstrated that the acceleration of quasi-isentropically and isentropically loaded liners under the conditions of high-level dynamics, symmetry of deposition, and suppression of shock-induced dusting is feasible.
An Erratum to this paper has been published: https://doi.org/10.1134/S106377612230001X
The results of experimental studies of the shock-induced particle ejection (“dusting”) from a free rough ( R z = 20) surface of lead and copper samples into an evacuated medium are presented. The experimental methods were based on different physical principles. To determine the size of particles by shadow laser-optical imaging more efficiently, a narrow strip was isolated in the center of the free surface of a sample from which an optically transparent stream of particles was ejected. The rest of the surface, substantially larger in size, ejected particles, parameters of which were reliably recorded using optical heterodyne interferometry detection, radiographic imaging, and piezoelectric techniques. This made it possible to obtain more reliable data on the particle size distribution, the velocity of the front of a particle flux, and the density (weight) distribution of the flow in the direction of its motion, necessary to refine the existing models and create more reliable models to describe the phenomenon. Using lead and copper samples, the material of which melts or does not melt under shock wave loading in selected close conditions (amplitude of the shock wave and roughness of the free surface), made it possible to clearly demonstrate the effect of melting on the qualitative pattern and quantitative characteristics of the shock-induced dusting process.
We report experimental results on studies of the interactions between various gases and the mass ejected from a shock accelerated surface. While such studies have been conducted in the past, data on such dynamic gas-ejecta interactions are incomplete. Therefore, along these lines, in the present work new comparative results are given concerning mass ejection from free surfaces of lead interfaced with vacuum or gas. The comparisons are made for the ejecta mass as a function of the surface roughness, the peak shockwave loading stress (amplitude) \(P_S\), and the release phase (state) of the post-shock metal.
The presence and behavior of a gas–metal interfacial layer at the free surface of shock-wave driven flying vehicles in gases of various compositions and densities has not been sufficiently studied so far. We present new comparative data on “dusting” from the free surface of lead into vacuum and gas as dependent on the surface roughness, pressure amplitude at the shock-wave front, and phase state of the material. Methods of estimating the mass flux of ejected particles in the presence of a gas medium at the free metal surface are proposed.
In view of the possible effect of contamination of a plasma by metal particles on the operation of a number of facilities or on the detection of the motion of liners by Doppler methods, a particular attention has been recently focused on the problem of the ejection of particles from the shock-loaded free surface of a sample or on the “dusting” problem. Most information concerns the dusting source associated with the roughness of the surface, manufacturing technology, and the defectiveness and aging of a material. Factors affecting this process such as the profile and amplitude of the pressure on the front of the shock wave arriving at the free surface of the sample, the presence of the gas in front of the free surface, and the pressure in this gas are less studied.
The possibilities of measuring complex Pylenie, which is intended for studying the parameters of the particles ejected from the free surface of a shock-loaded material and was created at the Institute of Experimental Gas Dynamics and Detonation Physics RFNC-VNIIEF, are demonstrated. The operation of the complex is based on the following three methods, which are based on different physical principles and supplement each other: laser-optical method (macro- and microfilming), pulsed X-ray method, and piezoelectric pressure sensors. This complex is used to study the ejection of particles from the free surface of lead samples when a shock wave with a pressure of 7, 16, and 23 GPa at its front reaches this surface. The effect of the surface roughness and the pressure amplitude at the shock wave front on the quantitative characteristics of the process is shown. The calculation-theoretical simulation is performed by two-dimensional numerical calculations of gasdynamic flows, and the calculation results are used to estimate the “ejecta” characteristics in terms of the developed phenomenological model of the process.
The details of the ejection of 20- to 200-µm particles with a velocity of 1.0-1.5 km/s from the surfaces of lead and steel samples with a roughness of 5-40 µm (Rz 5-Rz 40) when shock waves with an amplitude of 15 and 27 GPa reach them are visualized with a high-speed streak camera with a CCD matrix and pulsed laser illumination at a pulse duration of 4 ns. The size and velocity distributions of the particles are obtained.
The spectra of the optical losses in fibers were determined in the 0.8–1.6 μ wavelength range. A considerable change in the optical losses was observed under the influence of visible radiation and this was attributed to a photoinduced absorption of light because of a strong interaction of nonequilibrium carriers with localized states in the band gap of a glassy chalcogenide semiconductor. The photoinduced absorption was found to depend on the visible radiation intensity. The optical losses in the fibers made of chalcogenide glasses increased as a result of irradiation with a neutron dose of 1017cm−2 because of the appearance of additional defects which altered the surface state of the fibers.