No 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.

No abstract

No abstract

A statistical fragmentation model is presented, which predicts the average size and distribution in sizes of fragments emanating from an explosively driven, naturally fragmenting cylinder. The model builds on the energy-based fracture model of [Kipp and Grady, J. Mechanical Phys. Solids 33, 399 (1985)] by closing the calculation of average fragment size with the introduction of a crack velocity, which determines the time required for a newly initiated fracture to proceed to completion. Fracture energy is accounted for in the solution, resulting in a bimodal distribution function. Calculations are presented in comparison to experimental data for explosively driven metal sleeves and impact fragmentation. From comparison to existing fragmentation models and test data, we demonstrate the feasibility of the proposed approach.