Detonation Characteristics And Explosion Effects In Soil Of New Aluminized Explosives

As military composite explosives, Aluminized explosives have already been used to load air and underwater weapon warhead widely because of their excellent performance. However, with respect to traditional aluminized explosives, Production and processing technology of micron and nanometer aluminum is complicated, which may lead to industrial dust pollution and explosion, and improving the mechanical (impact, friction) sensitivity of composite explosives. Therefore, the above problems may be solved by changing the shape of aluminum, such as aluminum fiber and aluminum foil instead of aluminum powder being placed into mixed explosives. The technological thought about explosion cavity formed in rock and soil plays an important role in military and civilian field. Aluminum fiber explosive has obvious advantages over industrial emulsion explosive in energy output and mechanical properties, and can make up for deficiency about work efficiency of industrial emulsion explosive in some special environment. The energy output characteristics of new aluminized explosives are studied by several methods such as underwater explosion performance tests, field tests and numerical simulation of explosion cavity in soil. Main contents of the study are as follows:The shock wave pressure-time curves are obtained by underwater explosion tests of aluminum fiber explosive, traditional aluminum powder explosive and matrix explosive RDX. The related parameters of three types of explosives such as the shock wave peak pressure, impulse, specific shock wave energy, bubble pulsation period, specific bubble energy, and specific explosion energy are obtained by analyzing the curves. Aluminum fiber explosive has lower peak pressure but greater impulse than RDX, just the same as aluminum powder explosive. The peak pressure and impulse of aluminum fiber explosive are slightly lower than that of aluminum powder explosive in near measuring point, but tend to be equal in far location. The peak pressure attenuation rate of aluminum fiber explosive is slower than that of aluminum powder explosive. The specific shock wave energy of aluminum fiber explosive is greater than that of RDX by9.56-15.00%, lower than that of aluminum powder explosive by1.19～2.40%. The specific bubble energy of aluminum fiber explosive is greater than that of RDX by44.00～47.35%, greater than that of aluminum powder explosive by3.07～3.60%. The secondary reaction of aluminum fiber and detonation products mostly contribute to increasing specific bubble energy of explosives. The specific explosion energy of aluminum fiber explosive is greater than that of RDX by24.85～29.18%, greater than that of aluminum powder explosive by0.95～1.62%. The experimental data is credible with reasonable distribution according to data statistics and variance analysis.Aluminum foil explosive, obtained by mixing aluminum foil with RDX uniformly, is taken to compare with aluminum powder explosive on underwater explosion test. The decay rate of peak pressure of aluminum foil explosive is slower than that of aluminum particle explosive, the impulse and specific shock wave energy of them have the same results. The specific bubble energy of aluminum foil explosive is slightly greater than that of aluminum powder explosive due to the smaller specific surface area with high purity of aluminum of aluminum foil and the longer bubble pulsation period of aluminum foil explosive, so that the total energy of aluminum foil explosive is slightly greater than that of aluminum powder explosive. The experimental data is credible with reasonable distribution according to data statistics and variance analysis.The explosion cavity effects in soil of aluminum fiber explosive were studied by field test, and related semi-empirical formulas were concluded. Comparing with emulsion explosive, the horizontal radius of explosion cavity of aluminum fiber explosive is greater by15.6%, the vertical radius is greater by21.6%, and the volume is greater by54.1%, so that the work capability of aluminum fiber explosive is obviously improved. Meanwhile, based on the inclined problem of underwater explosion tower of5meter height, which is used for underwater explosion experiments, and in consideration of the condition of basic support of circular-distribution steel and local geology, charge weight and depth of each hole were elaborately designed by semi-empirical formulas. Due to the action of gravity and explosion vibration during the forming process of explosion cavities created by aluminum fiber explosive, the tower was adjusted to horizontal plane.For evaluating work capability of aluminum fiber explosive, the numerical simulation of explosion cavity expansion in soil is carried out by using analysis software ANSYS/LS-DYNA. The relationship between the radius of explosion cavity and explosive charge, explosive radius, and that between peak pressure of explosion wave of soil element near explosive and scaled distance were obtained. The secondary reaction of aluminum fiber and detonation products effectively delay pressure attenuation, can help improving work capability of explosive as supplement for shock wave energy.