Hameed, A.

Shukla, A.

Zagorecki, A.

English

Hameed, Amer

CERES Research Repository (Cranfield Univ.)

FATool SoftwareThe lethality analysis model presented on the right-hand-sidewas implemented as an analytic tool within the FATool softwareframework. FATool is implemented in the MATLAB modellingenvironment and is deployed as a stand-alone application.FATool is designed with a modular approach in mind allowingfor using different models for aeroballistics, lethality, etc. andbatch-running and parallelization.LETHALITY ANALYSIS BASED ON A FRAGMENTATION MODELFOR NATURALLY FRAGMENTING SHELLSAdam Zagorecki1, Amer Hameed2, and Anoop Shukla1,31Deepartment of Informatics and Systems Engineering, Cranfield University, Defence Academy of the United Kingdom, Shrivenham, Swindon, UK.2Centre for Defence Engineering, DEAS, Cranfield University, Defence Academy of the United Kingdom, Shrivenham, Swindon, UK.3Department of Mining Engineering, Indian School of Mines, Dhanbad, 826004, India.Method Overview0 100 200 300 400 500 600 700-300-200-10001002003000 100 200 300 400 500 600 700-250-200-150-100-50050100150200250FRAGMENTATION MODELThe original 2D shape isconverted into a sphere todetermine initial velocities usingthe method developed byJayaratnam in 2001.Fragmentation model is based onSzmelter 2003, but wassignificantly improved.The model results with thefollowing for each fragment:• Initial velocity vector• Initial position• Shape class• Width, length, and heightAEROBALISTIC MODELA trajectory for each individualfragment is calculated:• Drag coefficient is determinedbased on shape and velocity• Drag coefficient model basedon McCleskey (1988)LETHALITY MODELSDifferent lethality functions canbe used, currently available:• Thresholded Kinetic Energy• Cost-augmented functionbased on Kinetic Energy• Lethality function based onSperrazza and Kokinakis (1968)that accounts for velocity andshape of the fragmentAbstractIn this paper, we analyze the lethality effects of explodingnaturally fragmenting warhead by computing a threedimensional fragment distribution around the warhead. For thefragment generation we modified an earlier proposed methodthat uses a transformation of a general geometrical shape to ahollow sphere, subsequently applying the Gurney’s principles.The method allows for prediction of fragment velocity vectors’distribution. Another method was used to model thefragmentation process and that method allows for capturingfragments’ masses, sizes and classes of shapes. Consequently,the air drag equations are applied to calculate the trajectory ofeach fragment. For lethality analysis we used the kinetic energysupplemented by other fragment parameters to computelethality effects. We proposed a general approach to calculatelethality as a function defined over a volume. We exploredseveral basic lethality functions and discuss differencesbetween them. We claim that the approach presented can beused to analyze lethality on complex shapes. A set ofexperiments based on an actual artillery shell is included toprovide validation of the approach is presented.REPORTING RESULTSThe approach assumes that thearea is uniformly covered withtargets and the distribution ofprobability of kill is calculated foreach point on the grid (50cm x50cm grid by default). Sinceresults are non-deterministicmultiple simulations are necessaryto determine averaged effect.Around 200 simulations is neededto provide robust estimates.ResultsThe software simulations were able to recreate empiricalfragmentation patterns. The effects of terminal and rotationalvelocity can be visualised and quantified in terms of lethaleffects.ApplicationsOnce properly validated, the software tool can provide cost-effective and method for estimating lethality effects of variousdesigns of shapes, compositions, terminal velocities, etc.Kinetic Energy Distributionfor a Static ShellKinetic Energy Distributionfor a Shell Travelling at 300 m/s

Lethality analysis based on a fragmentation model for naturally fragmenting shells

http://dspace.lib.cranfield.ac.uk/bitstream/1826/7735/1/FAToolPoster.pdf

Lethality analysis based on a fragmentation model for naturally fragmenting shells

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