Impact Analysis Of High Pressure Fragmentation

Abstract

Damage due to explosive is second to none amongst the threats faced by Pakistan. It’s damaging not only the economy, political stability, social sector, but also national security and integrity. The threats from a conventional explosive based shell depend on two parameters, the charge weight and the distance between fragmentation point and the target. Materials used in explosive shells can be characterized on the basis of their nature as solid, liquid or gaseous. Unwanted blast events such as terrorist attacks with improvised explosive devices or unexploded ordnance accidents are a constant threat to our present-day society. Injuries can be due to the energized fragments flying through the air and it can af fect any part of the body. A profound understanding of this phenomenon is required for the estimation of potential hazards from the fragments generated by detonating ammunition items. The fragment formation due to release of high energy from explosive shell is a random process and cannot be defined exactly. Therefore probabilistic approaches are gener ally used for the assessment of fragment and their hazards. The fragments produced from the detonation of a single shell can be characterized by their fragment numbers with respect to fragment mass, and initial velocity. The basis of this research is to estimate the terminal impact of fragments produced in 2-D and 3-D fragmentation of cylindrical shell. Statistical formulation is used for estimation of fragment mass in both cases. Fragment trajectories under the action of constant drag and Gravity are calculated from three dimensional equations of motion. Fragmentation of explosive shell depends on number of factors, like geometric shape and size, angle of attacked. In this study a fragment throw model which consider the drag, area, mass and air density as input parameters is used to predict the flight trajectory of fragments. To analyze the terminal impact, range and dispersion of different types of fragments, probabilistic modeling is used. We used Mott Distribu tion for 2-D and 3-D fragments masses. The final deliverable is the development of a generic frame work, the dispersion graphs and probability damage at three different positions.