Composite Material Particle Impact Mitigation Sleeve Testing

Abstract

This paper will present the results from four series of Fragment Impact (FI) tests on the TOW 2B warhead utilizing multiple Particle Impact Mitigation Sleeve (PIMS) configurations. Previously it has been demonstrated that the addition of a plastic, typically ULTEM ® 1000, PIMS reduces the sensitivity of a munition to the FI threat. The mechanism by which the sensitivity is reduced is the reflection of the shockwave at the interface between the PIMS and the munition case material. The munitions to which this protection scheme has been applied previously use PBXN-9 as the main fill explosive and are therefore easier to protect using a single component PIMS than TOW 2B, which uses LX-14 as the main fill. LX-14 is a more sensitive explosive than PBXN-9, and requires additional material in the shotline to reduce the shock pressure in the explosive via reduction of velocity, breakup of the incoming fragment, and shock reflection at the interface between the case and the PIMS. The test results demonstrate that TOW 2B can be protected using a plastic PIMS in combination with a second layer of hard material spaced from the munition to break the fragment and slow it down prior to impact with the PIMS.

Insensitive Munitions Fragment Impact Gun Testing Technology Challenges

“…In order to investigatea nd understand some of the causes for munition response variations to projectile tilt, ALE3D computational impact studies were additionally conducted. As eries of impactsw as conducted againstageneric 155 mm outsided iameter L/D = 1.5 4340 steel cylinder filled with PBXN-9 and cappeda tt he ends, with and without ah igh density polyethylene internal particle impact mitigation sleeve (PIMS) [7,8].T he steel body thickness was 8.6 mm, and the PIMSw as 2.7 mm. To examine the effect of projectile tilt, models using tilts of 0a nd 108 were conducted using an impact velocity of 2530 ms À1 .T he results are presented in Figure 11.Itc an be clearly seen thatsignificant differences in shock and penetrationp rocessp ressures are noted for the different projectile tilts.…”