Damage and fracture prediction of plastic-bonded explosive by digital image correlation processing

By digital correlation processing of Scanning electronic microscopy (SEM) images, the paper presents the deformation and damage analysis of an energetic material—the plastic-bonded explosive (PBX) on mesoscopic scale. The analysis is made by observing the deformation field resulted from the digital image correlation (DIC) processing of the images corresponding to the loading steps and comparing with the surface profiles of the composite material so as to visualize the matter damage near a preset crack. The results show that the local deformation disturbance can reveal the material damage even happened underneath the specimen surface. The strain distribution in the front of the preset crack, can be used to predict the propagating route of the microcrack initiated from the tip of the pre-crack, which is related to the splitting fracture of the granular-based composite under compressive loading.     

Mechanism of wave formation at the interface in explosive welding

Some of the main progress on the investigation of the mechanism of the wave formation in explosive welding at the Institute of Mechanics is summarized and others' previous works are reviewed. Our systematic experiments and analysis do not substantiate the theory of wave formation based on Karman vortex-street analogy or Helmholtz instability. On the contrary, they show that material strength insensitive to strain rate plays an important role. A simple hydro-plastic model is presented to explain the main features regarding the interfacial wave formation and to estimate the magnitude of wave length. The result is in broad agreement with experiment.     

Shock wave working of high-T c materials

Abstract

The properties of high T_c-ceramics (Y-123, Bi-1112, Bi-4334, Bi-4457, (Bi-Pb)-4457) under shock loading and subsequent heat treatment were investigated. The peculiarities of their structure, tecture creation, changes of superconductivity parameters depending on loading conditions at P～ 10GPa Were revealed, and regimes of heat treatment were determined. The possibilities of obtaining crack-free cylindrical superconducting shields as well as strong metal high-T^cceramic joints were demonstrated.     

Highly efficient formation of metal and metal alloy particles from methyl metal compounds by a single pulse laser irradiation

Highly efficient processes for fine particle formation of metal alloys and metal oxides were developed using a high-power laser. In these processes, laser light was used only for the ignition of a thermal chain reaction. This reaction was suppressed by adding inert gases, and the suppression effect was in the order C₃H₈ > C₂H₆ > CH₄ > He > Ar > Xe. Oxygen accelerated the reaction because of the large exothermicity of the reaction of oxygen with methyl metal compounds.     

具奇异边界条件的一类拟线性椭圆型方程

得到了一类拟线性椭圆型方程爆破解的存在性。     

A first experimental approach to the 15O + α elastic scattering

The ¹⁵O(α,α)¹⁵O elastic scattering is investigated using a ¹⁵O radioactive beam and a He gas cell limited by Mylar windows. The width of a ¹⁹Ne state at an excitation energy of 5.35MeV is measured as Γ_α = 3.2±1.6keV, in agreement with charge symmetry estimate.     

硝酸铵的一种敏化技术

介绍一种在表面活性剂作用下，采用真空改性结晶技术，制备膨松、轻质和多微孔隙硝酸铵的方法。用该硝酸铵混制的铵木油炸药，具有良好的起爆和传爆性能、作功能力大、爆速高，是一种可以取代铵梯炸药，适宜于工业生产和广泛用于工程爆破的炸药。     

Generation and evolution of cavitation in magma under dynamic unloading

The full system of equations for the problem of rarefaction-wave passage over the magma-melt column in the gravity field is derived with the use of the kinetic theory of phase transformations, and the problem is numerically solved. With allowance for diffusion zones and nucleation frequency as a function of supersaturation, the dependence of the number of cavitation nuclei formed in the course of phase transformations behind the rarefaction-wave front is found. The dynamics of the size distribution of cavitation bubbles along the magma-melt column (1 km) whose viscosity varies dynamically as a function of the concentration of dissolved water is studied.Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 46, No. 2, pp. 71–80, March–April, 2005.     

爆炸作用数值模拟

采用简单的炸药化学反应率方程，利用二维流体弹塑性流动程序，对一个变直径铜壳中装药的爆炸作用做了数值模拟。     

在两层不同爆速炸药滑移爆轰作用下飞板运动的数值计算研究

本文研究用低爆速炸药复盖高爆速炸药在定滑移爆轰作用下飞板运动的计算方法,并对惯性复盖与炸药复盖的结果作出相互比较。