An approach for calculating non-stationary thermo-gasdynamic processes in model chambers of solid rocket engines is described. A three-dimensional mathematical model of viscous multicomponent gas mixture is an extended system of Navier-Stokes equations with the component diffusion equations. The computational model and the computer code are based on the developed original mathematical methodology that combines the advantages of splitting method by physical processes, robustness of Godunov's scheme for the convective stage and efficiency of explicit iterative Chebyshev’s scheme for diffusion stage. The code is written in C++ and uses a hybrid three-level parallel structure, including the use of MPI, OpenMP and CUDA technologies.

Changes in the chemical and phase compositions, as well as the formation of micro- and nanostructured objects in syntactic foams consisting of tungsten-modified glass microspheres and a polymeric binder based on a phenylsilsesquioxane— b -dimethylsiloxane block copolymer, caused by the action of a single relativistic electron beam with an average energy in the range of 180–260 keV and a peak current power in the range of 4.5–6.8 GW were studied by scanning electron microscopy and X-ray phase analysis. It was demonstrated that tungsten and tungstic acid hydrate react with products of polysiloxane decomposition to give WO 3 , WO 2 , δ-WO 2 , and Na 2 WO 4 under extreme conditions ( T > 1600 K and pressures in the range of 3–8 GPa) near the surface of the microspheres. The observation of irregularly shaped droplets and “solidified foam” structures found on the inner surface of collapsing microspheres suggests that the formation of filamentous structures is preceded by high-temperature reactions involving products of high-temperature pyrolysis of polysiloxane and tungsten compounds.

The destruction of an energetic condensed system based on glycerol trinitrate, polyether urethane, and aluminum powder upon exposure to a relativistic electron beam with a maximum energy of 310 keV, a total duration of 170–180 ns, and an average flux density of 200–215 J/cm2 was studied by nanosecond electron-optical chronography, scanning electron microscopy, and energy dispersive analysis. The effect of the generation of pulsed electric fields and shock-wave loads accompanying relativistic electron beam absorption on the mechanical damage to samples of energetic condensed systems is discussed.

Changes in dielectric properties and thermal stability of the alpha-aluminum hydride polymorph (α-AlH3) after irradiation with electrons with an energy of 7 MeV were studied by dielectric spectroscopy, differential scanning calorimetry, thermogravimetry, and powder X-ray diffraction. Dielectric relaxation was observed in α-AlH3 samples irradiated using an electron beam with a frequency of the electric field of more than 5 MHz. The dielectric properties of α-AlH3 samples depend on the absorbed dose and the duration of time elapsed after the cessation of irradiation, while the temperature of the onset of decomposition and the kinetics of thermal decomposition of α-AlH3 samples vary little for absorbed doses up to 160 kGy. Radiation-chemical yield of the formation of the metallic phase during α-AlH3 radiolysis was determined by potentiometric titration.

Transformations caused by the action of a relativistic electron beam with the half-amplitude pulse duration of 100 ns and power of 6.3–9.2 GW on a syntactic foam formed by glass microspheres and siloxane block copolymer and on the polymer base of the syntact were studied by scanning electron microscopy and X-ray diffraction. The collapse of glass microspheres in the syntactic foam under the action of the relativistic electron beam leads to the formation of elongated structures of micrometer size and of whisker structures with the minimal diameter of 40 nm (nanofibers). The distribution of the fields of absorbed doses and shock wave pressure was estimated using Monte Carlo methods. The revealed changes in the chemical and phase composition of the syntactic foam and its polymer base, caused by the single action of the relativistic electron beam, are discussed.

This paper presents the results of a study of the impact of a high-current electron beam of the Kalmar accelerator with a cutoff electron energy of up to 350 keV on igdantine and low molecular weight nitrile butadiene rubber SKN-18-KTR. The materials are similar in mechanical and physical properties, but differ in chemical structure. It has been shown that, at a beam energy of less than 600 J, the destruction of igdantin begins to a depth significantly exceeding the electron range, while nitrile rubber withstands a load of more than 700 J without significant damage. It is demonstrated that the dynamics of plasma expansion from the surface of igdantin regularly demonstrates specific.

The relationships of the action of a relativistic electron beam from the Kal’mar accelerator on the syntactic foam formed by glass microspheres distributed in an elastic polymer matrix of cured butadiene–acrylonitrile rubber, reinforced with chrysotile fibers, were studied by electron microscopy, X-ray diffraction, and electron-optical chronography with nanosecond time resolution. Under the action of pulsed (~100 ns) electron beam with the power of 6.2–7.55 GW and electron energy of up to 310 keV, a crater with characteristic fused inclusions is formed on the syntactic foam surface, and the initial velocity of spread of the gas plasma formations reaches 19 km s–1. The ablation products contain clusters of glass sphere fragments, short chrysotile asbestos fibers, and polymeric binder. The action of high temperatures and pressures generated by the relativistic electron beam leads to collapse of glass spheres and to changes in the phase composition of the syntactic foam.

A scanning electron microscopic study has shown that exposure of spheroplastics based on an organosilicon elastomer to a microsecond shock-wave pulse causes the formation of whisker structures up to 10  $$\mu$$ m long. Whisker structures are formed on the surface of fractured microspheres. Their formation is facilitated by the metallization of the surface of glass spheres. The paper presents the results of an experimental study of changes in the dielectric and mechanical characteristics of a metallized spheroplastic under shock-wave loading. Possible reasons for the formation of whiskers during shock-wave loading of spheroplastics are discussed.

The modern state of experimental and theoretical studies of the radiation-induced conductivity and charging of polymeric dielectrics under the action of electron beams is considered. The effect of the molecular mobility on the transport of excess charge carriers is discussed.

An experimental study was made of the initiation of detonation of a polymer-bonded energetic condensed system containing glycerol trinitrate, ammonium perchlorate, and aluminum powder by a nanosecond relativistic electron beam with a flux density of 200 J/cm2. It has been found that the velocity of dispersion of gas–plasma formations from the surface of the energetic condensed system is ∼22 km/s. It has been shown that the detonation of the studied energetic condensed system by the nanosecond relativistic electron beam is reached at much lower pressures than in the case of initiation by an explosive charge.

The article presents experimental results of changes in the dielectric and mechanical characteristics of spheroplastics based on an organosilicon elastomer and metallized glass microspheres caused by static and shock compression. Two regions of the frequency dispersion of the dielectric constant are established that are associated with the metal coating of microspheres. It was found that both the low- and high-frequency dispersions of the complex dielectric constant decrease sharply at a relative compressive strain of no less than 70%. Possible causes of the detected change in the complex permittivity are discussed.

Представлены экспериментальные результаты изменений диэлектрических и механических характеристик сферопластика на основе кремнийорганического эластомера и металлизированных стеклянных микросфер, вызванных статическим и ударным сжатием. Установлено наличие двух областей частотной дисперсии диэлектрической проницаемости, связанных с наличием металлического покрытия микросфер. Обнаружено, что при относительной деформации сжатия не менее 70% наблюдается резкое снижение как низкочастотной, так и высокочастотной дисперсии комплексной диэлектрической проницаемости. Обсуждены возможные причины обнаруженного изменения комплексной диэлектрической проницаемости. Ключевые слова: сферопластик, микросферы, диэлектрические характеристики, механические характеристики.

The formation of nanowhiskers in tungsten-containing syntactic foam under nanosecond relativistic electron beam has been experimentally studied. It has been demonstrated that a single impact of relativistic electron beam with a flux density of 230–240 J/cm2 and a total pulse duration of 150 ns on syntactic foam leads to the collapse of microspheres of more than 40 μm in diameter with the formation of filamentous structures up to 10 μm in length and about 100 nm in diameter on their surface. There is complex kinetics of substance ablation from the irradiated surface at a gas-plasma formation expansion rate of ~13 km/s. It has been found that nanowhiskers do not form near the emission “crater” from syntactic foam where the duration of the mechanical pressure pulse is minimal and close to the relativistic electron beam impact.

This paper describes the effect of the composition of energy condensed systems, containing glycerol trinitrate, aluminum powder, ammonium perchlorate, and HMX, on their ignition in an electric field with a frequency of 50 Hz. Conditions under which energy condensed systems ignite in an alternating electric field with a frequency of 50 Hz are determined experimentally. Temperature changes of their dielectric characteristics in a frequency range from 20 Hz to 1 MHz are established. The possibilities of an electric breakdown and heating of the samples are theoretically estimated. It is revealed that electrical luminescence is observed in a polymer binder based on glycerol trinitrate and polyetherurethane.

The paper is devoted to the numerical simulation of the electromagnetic field propagation in a complex heterogeneous material with the direct resolution of its microstructure. The electromagnetic field dynamics is described using full non-stationary system of Maxwell's equations. Geometrical model of the material structure is developed using well-known Lyubachevsky-Stillinger sphere packing algorithm and event-based molecular-dynamic simulation approach. Comparison between simulation results in heterogeneous material and in effective homogeneous one is presented and discussed. The results of the simulation allow to obtain both the full structure of the electromagnetic field distribution and the assessment of the influence of the material inhomogeneities on the electromagnetic field propagation. Besides, the effective properties of the medium are computed using simulation results.

The temperature–frequency dependence of the complex elastic modulus of an adhesive composition based on unsaturated polyketone was studied by dynamic mechanical analysis. It was shown that, in the temperature range of –100 to +60°C, two relaxation processes occur, which are related to the presence of two polymer networks in an adhesive composition. The regularities of the effect of γ radiation on the temperature dependence of the complex elastic modulus of an adhesive composition were established.

Приводятся результаты экспериментальных исследований формирования нановискеров при воздействии релятивистских электронов наносекундной длительности на сферопластик, содержащий в своём составе вольфрам. Показано, что при однократном воздействии релятивистских электронов с плотностью потока 230-240 Дж/см 2 и полной длительностью импульса 150 нс в сферопластике наблюдается разрушение микросфер диаметром более 40 мкм, на поверхности которых образуются нитевидные структуры длиной до 10 мкм и диаметром около 100 нм. Установлена сложная кинетика уноса вещества с облучаемой поверхности при скоростях разлёта газо-плазменных образований ∼13 км/с. Обнаружено, что нановискеры не формируются вблизи “кратера” выброса из сферопластика, где длительность механического импульса давления минимальна и близка к продолжительности действия релятивистских электронов.

This paper describes the experimental study of dielectric relaxation in energy condensed systems based on ether urethane rubber plasticized by glycerin trinitrate and ammonium perchlorate, HMX, and aluminum powders in the frequency range of the electric field from 40 to 1.2 · 109 Hz. Depending on the field frequency, it was possible to determine relaxation processes caused by dipole polarization, the bulk electrical conductivity of a polymer binder, and the influence of the surface of aluminum particles.