Experimental study on velocity attenuation law of fragment simulated projectile

DOI:	10.11809/bqzbgcxb2024.02.007
Keywords:	FSP fragments; velocity attenuation; attenuation coefficient; air resistance coefficient; experimental test
Abstract:	For the problem of the motion law of FSP fragments in the air used in the evaluation test of material protection performance, a fragment simulation projectile is designed and proposed, which meets the NATO STANAG 2920 “Ballistic Test Method for Armor Materials and Protective Clothing” standard. The velocity attenuation law of fragments moving in the air within 9~27 m from the muzzle was studied by means of experimental research, numerical simulation, and theoretical analysis. The fragment simulation projectile was launched by a 30 mm ballistic gun, and the velocity data of fragments in the range of 900~ 1 100 m/s were obtained by using multiple sets of zones cutting devices. The velocity attenuation model was established based on the motion equation of fragments, and the extreme value of the windward area during the movement of fragments was derived. The results show that the maximum error between the simulation and the measured speed is 1.69%; the fragment velocity attenuation coefficient k is 0.005 36, and the established fragment velocity attenuation model is v=v0×e -0.005 36x ; the air drag coefficient of the fragment cx is only related to the angle between the axis and the horizontal plane, and the value range is ［0.867 8, 1.404 5］. Through experimental verification, the fragment velocity calculated by the established fragment velocity attenuation model is consistent with the measured data, which can accurately predict the velocity of FSP fragment at a given position point within 27 m from the muzzle. When carrying out the material protection performance evaluation test with a protection level of 5, the distance between the gun and the eye can be taken as 25 m.
Published:	2024-02-28
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