A Comparison Investigation on Cylinder Test in Different Ambient Media by Experiment and Numerical Simulation

When the detonation reaction occurs after the charge in the warhead is ignited, the propagation of the detonation wave and the expansion of the detonation product will interact with the wrapped metallic shell and cause the shell material to accelerate, extremely deform, and eventually rupture, which is a typical strong fluid-structure interaction problem. In this paper, a comparison investigation on a cylinder test in different ambient media was implemented by experiment and numerical simulation, respectively. In the experimental test, the attention was paid to discussing the differences of the accelerating process of the cylinder metal wall, the expansion modes, and the fragment shape of the cylinder due to the medium with different shock wave impedance which surrounds the cylinder shell. For the numerical simulation, a coupling scheme of a meshless method and finite element method called the coupled finite element material point method was used to reproduce the cylinder expansion problem driven by explosive sliding detonation where the interaction between the cylinder wall and the explosive/detonation product is enforced by using a point-to-surface contact scheme to accurately achieve contact and separation between material particles and finite elements. Lastly, the macroscopic and microscopic states of the cylinder failure were compared and discussed for further discussion.

Numerical Simulation on Dynamic Laval Nozzle under Different Detonation Model

In conventional charge structure, the shell of charge’s containment is normally closed, with no explosive. When initiating charge, shell expanding to the outward, rupturing and eventually spreading out which was driven by the charge, this don’ have a guiding role to the detonation product flow. To further enhance the control of charge’s detonation product and energy flow, realizing the effective use of detonation products. The thesis put forward a structure design of filling thin-layer explosive in multi-layer shell, by initiating thin-layer explosive to control the deformation of shell, obtaining a approximately function with Laval Nozzle structure which can control the gas product when charge detonation. The thesis put forward a structure that including multi-layer explosive shell, establishing a numerical simulation model. Analysis the difference of shell’ deformation on different initiation method, provides a design references for further engineering application.

Pressure Measurements of Aluminized Explosives Detonation Front with Different Aluminum Particle Size

Detonation pressure profiles in TNT/RDX and its mixtures with aluminum powders of different particle size have been studied with Manganin piezoresistance gauge. The measured detonation pressure accorded with the calculated detonation pressure. The results show that micrometer aluminum powders reacted with detonation at times of 0.5μs after the peak pressure. Aluminum powders did not react in the detonation zone, and introducing aluminum into explosive would reduce the detonation pressure. Compare with micrometer aluminum powders, nanometer aluminum powders reacted with detonation product more quickly.

Numerical Simulation of Small-Scale Explosion in Dry Sand

Numerical simulation of small-scale explosion in dry sand using two sand material models including the Sand model and the LA model were carried out in the present study. Three cases were considered which the depths of burial (DOB) of the explosive C4 charge were 0, 30 mm and 80 mm, respectively. The time arrival of the blast-wave front and the maximum overpressure of fixed measuring locations were studied using a two dimensional axisymmetric model in hydrocode ANSYS/AUTODYN. Furthermore, the crater diameters and the heights of detonation product cloud respect to the time were also studied by comparing with the test data. The simulation results indicate that the both sand material models were hardly predict the test data exactly which proves that the sand properties and the material model should be more carefully studied and defined.