Study On Structural Integrity Of Explosive Excavated Explosive Excavation

Energetic fragment is a new kind of high-efficient damage unit. It releases its chemical energy when penetrating the target, which will lead to ablative, igniting, detonating the internal structure of target. Energetic fragment has both kinetic and chemical damage effect. Research on Energetic fragment has received wide attention in effective damage area in recent years.The explosive-driven process and deformation/fracture mechanism of case-wrapped. Energetic fragment has been studied in this thesis by combining theoretical analysis and numerical simulation. The calculation model on initial velocity of energetic fragments has been established. Key factors effecting the deformation/fracture mechanism of case-wrapped Energetic fragment was evaluated. The optimized structure of energetic fragment warhead has been proposed.The Results has been verified by experment. The main contents and conclusions are as follows:(1)The calculation model on initial velocity of case-wrapped energetic fragments.The calculation model on initial velocity of energetic fragments has been established based on momentum theory by simplification of existing models. Compared to existing models, this model considered the effect of liner and deformation of fragments on the initial velocity. The model was also verified by numerical simulation.(2)A model on the initial pressure of energetic material in the fragment was proposed based on one-dimensional shock wave theory.Based on the one-dimensional shock wave theory, A model on the initial pressure of energetic material in the fragment was proposed by ignoring the effect of shock wave propagation in the media, this model was employed to calculate the initial pressure of energetic material with several different liner materials. According to the calculation results, the optimizing material of Energetic fragment war head liner and case has been selected.(3)the deformation/fracture mechanism of the case was investigated.A two-dimensional simulation model of case-wrapped energetic fragment warhead has been set up using finite element analysis software AUTODYN.The effect of liner thickness on the fragment velocity and deformation has been studied by theoretical analysis and simulation calculation. These results were employed to verify the initial velocity calculation model. The deformation/fracture mechanism case was investigated by combining theoretical calculation and numerical simulation. The optimized structure of energetic fragment warhead has been proposed.(4) The results has been verified by explosion driven gun in parts.The integrity of two types Energetic fragments which has different wrap has been studied by explosion driven gun. The result suggest that fragments which has double steel wrap shell keep good structural integrity, however, the tungsten alloy wrap has fractured, it indicted that tungsten ally not suitable as the material of Energetic fragments’wrap shell. Theoretical analysis and simulation results has been confirmed by experiment in parts.