EXPRESS METHOD FOR CALCULATING THE SPECIFIC HEAT OF EXPLOSIVE TRANSFORMATION OF CHNO CONDENSED EXPLOSIVES

Разработан экспресс-метод расчета теплоты взрыва СаHbNcOdконденсированных взрывчатых веществ с различным кислородным балансом от резко отрицательного до положительного. Предложенный метод использует минимальный набор входных данных, состоящих из элементного состава, плотности энтальпий образований исходного взрывчатого вещества и его продуктов детонации. Расчет теплоты взрыва основывается на корреляционной связи между минимальной и максимальной теплотами взрыва с плотностью высокоэнергетического соединения. В статье подробно приведены реакции разложения взрывчатых веществ для случаев с минимальной и максимальными теплотами взрыва. Проведены расчеты теплоты взрыва по новому способу и методу Пепекина по представленной в статье базы взрывчатых веществ, а также приведены результаты сравнения, которые показали большую точность (в 2,3 раза) предложенного метода. An express method has been developed for calculating the explosion heat of cahbncod condensed explosives with different oxygen balance from sharply negative to positive. The proposed method uses a minimal set of input data consisting of the elemental composition, enthalpy density of the formations of the initial explosive and its detonation products. The calculation of the heat of explosion is based on the correlation between the minimum and maximum heat of explosion with the density of a high-energy compound. The article describes in detail the decomposition reactions of explosives for cases with minimum and maximum explosion heats. Calculations of the heat of explosion according to the new method and the pepekin method are carried out according to the explosives database presented in the article, and comparison results are also presented, which showed a better accuracy (2.3 times) of the proposed method.

Equations of state for detonation products of explosives

A comparative analysis of the equations of state for the detonation products of condensed explosives, which are most used in solving problems of the mechanical action of an explosion, is presented. For the most widespread (cited) equations of state of explosion products in the form of JWL, methods and algorithms are proposed for determining the correctness of specifying the coefficients included in this equation. To solve radiation-gasdynamic problems, including multicomponent mixtures, a version of the thermal equation of state of explosion products in the form of JWL is proposed, and a constant set for the most common explosives is recommended.

Determining the Velocity of Hypersonic Compact Elements in Ground Testing Plants

Protection of spacecraft from high-speed impact when encountering meteorite particles and man-made debris is currently a pressing issue. This article presents methods for determining the reaction of complex structures to the impact of particles with cosmic velocities. To determine the anti-meteorite resistance of materials and structures and to study the reaction of materials under high-intensity shock loading, schemes are developed for the production and registration of high-speed metal compact elements moving at hypersonic speeds using cumulative explosive throwing devices based on high-power condensed explosives. The use of the ‘hemisphere-cylinder’ shaped lining made it possible to test a shaped charge, consistently forming a steel compact element with a velocity of 6 km/s. The paper presents the results of numerical calculations and experimental testing of such a booster. Using this device, a method for determining the speed of the hypersonic striker pin is developed based on visualization of the head shock wave at the entrance of the striker into water.

NUMERICAL SIMULATION OF YIELDING SUPPORTS IN THE SHAPE OF ANNULAR TUBES UNDER STATIC AND SHORT-TERM DYNAMIC LOADING

Occurrence of extreme man-made impacts on buildings and structures has become frequent lately as a consequence of condensed explosives or explosive combustion of gas- vapor or air-fuel mixtures. Such accidents involve large human and economic losses, and their prevention methods are not always effective and reasonable. The given research aims at studying the way of enhancing explosion safety of building structures by means of yielding supports. The paper presents results of numerical studies (finite element, 3D nonlinear) of strength and deformability of yielding supports in the shape of annular tubes under static and short-term dynamic loading. The degree of influence of yielding supports was assessed taking into account three peculiar stages of deformation: elastic; elasto-plastic; elasto-plastic with hardening. The methodology for numerical studies performance was described. It was established that rigidity of yielding supports influences significantly their stress-strain state. The research determined that with increase of deformable elements rigidity dependency between load and deformation of yielding supports in elastic and plastic stages have linear character. Significant reduction of dynamic response and increase of deformation time of yielding supports was observed by increasing the plastic component. Therefore it allows assuming on possibility of their application as supporting units in reinforced concrete constructions