Projectile mass distribution following impacts on hardened steel plate

Stephens, John (2016) Projectile mass distribution following impacts on hardened steel plate. [USQ Project]

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Abstract

Hardened steel plate is a commonly used material for reusable targets in shooting clubs, particularly pistol clubs. The use of this plate creates safety concerns as the bullets are destroyed on impact and the bullet mass is deflected in sometimes unpredictable directions. Eye protection is mandatory in situations where steel targets will be shot at close range, however the relationship between shooting club organisers and the Police Weapons Licensing branch can often be strained in disagreements as to whether steel targets are being used appropriately.

The aim of this research project has been to gain a greater understanding of the behavior of lead projectiles after impact with steel plates, particularly the way in which the projectile fragments are distributed upon impact and the relationship between that distribution and the impact angle of the projectile against the target surface. This research will be beneficial to the relevant shooting sports where steel targets are used. It will assist competition organisers in setting targets and knowing what extra measures may be required for the safety of shooters.

The preliminary research of this report led to the selection of Bisplate 500 as the experimental target material, due to its common use as a target material and its availability. The rifle selected for the experiment was chambered in 32-20 Winchester. The legal limitations on where pistols are permitted to be used led to the decision to use a rifle instead as it allowed the testing to be undertaken on private property. The 32-20 cartridge fires a 115 grain (7.45 gram) lead-tin alloy projectile, very similar to the 9mm and .38 super projectiles most commonly used in pistol target shooting.

The experimental component of this research project involved both computer simulation and field testing of projectile impacts on hardened steel plate. The field testing revealed that the projectile fragments are deflected away from the impact site on the plane made by the face of the target. As the impact angle is reduced the fragments are still deflected on the same plane, however eventually the distribution of the fragments becomes biased to the lower side of the target. The critical angle at which there are no longer fragments deflected in all directions is 27.5°. At 24° the fragments are completely deflected below the impact point.

The ANSYS simulations produced results that reinforced the findings of the field testing at impact angles between 90° and 65°. At 65° the ANSYS simulations began to show the fragment distribution become biased toward the lower side of the target and see the beginning of a section at the top of the fragment pattern where there was no evidence of fragments, something not seen in the field testing until 27.5°.

The recommendations at the conclusion of this research project are that the safest way to setup steel targets on a range is to ensure that the plates are as close to perpendicular to the shooting positions as possible. It was identified that because the fragments are predominantly contained within a narrow plane of travel, they would be easily contained within a loop of absorbent material such as rubber conveyor belting.


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Item Type: USQ Project
Item Status: Live Archive
Additional Information: Bachelor of Engineering (Honours) Major Mechanical Engineering project
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering
Supervisors: Malpress, Ray
Date Deposited: 24 Jul 2017 01:21
Last Modified: 24 Jul 2017 01:21
Uncontrolled Keywords: rubber conveyor belting; hardened steel plate; projectile mass distribution; computer simulation; field testing
Fields of Research : 09 Engineering > 0913 Mechanical Engineering > 091304 Dynamics, Vibration and Vibration Control
URI: http://eprints.usq.edu.au/id/eprint/31491

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