Effect of electromagnetic launch on armature/sabot discard

This paper presents the validation of a sabot discard model, developed at t he Institute for Advanced Technology (IAT), for predicting armature/sabot s eparation, and quantifies the effect of electromagnetic launch on sabot dis card as well as on the sub-projectile, The experimental data used to valida te the model were obtained at the Army Research Laboratory (ARL) Transonic Experimental Facility at Aberdeen Proving Ground, R ID, Five shots were con ducted at a nominal velocity of 1350 m/s and armature/sabot petal trajector ies were reduced from x-ray images taken at six downrange stations. The res idual electromagnetic force on the launch package after muzzle exit was als o determined from experimental data. The sabot discard model uses analytica l expressions to estimate surface pressure distributions, which are then in tegrated, in a time-marching algorithm, for linear and angular acceleration s, and subsequently for sabot petal trajectories, The most significant attr ibute of this model is that it does not rely on any empirical data for mode ling and is therefore expected to be widely applicable, The results from th is study have shown that the comparison between predicted and measured arma ture/sabot petal trajectories is excellent, Furthermore, the model has demo nstrated quantitatively the delayed armature/sabot discard caused by the re sidual electromagnetic force and the additional deceleration of the sub-pro jectile due to the delayed mechanical disengagement.