Damage-Sensitivity Correlations in Explosives
Abstract
As energetic materials are subjected to increasingly extreme environments, the effects of damage on changes in sensitivity at a fundamental level need to be better understood. To that end, a variety of experiments have been conducted on a plastic-bonded explosive. Shock Wave Apparatus (SWA) and Modified Gap Tests (MGT) were conducted based on similar tests performed at Gesellschaft fur verteidigungstechnische Wirksysteme (TDW). X-Ray Computed Microtomography (XCMT) was conducted on the damaged explosive and the results analyzed using a MATLAB routine which quantified damage in the samples. In addition, a series of confined Split- Hopkinson Pressure Bar (SHPB) tests have been performed on an explosive simulant to understand the effects of confinement on the polymer binder and simulant, as the polymer binder exhibits substantial pressure sensitivity. SWA and MGT results suggest that damage increases sensitivity for initiation pressures below 3.5 GPa, while for pressures above 3.5 GPa the sensitivity of the explosive remains largely unchanged. Results from quantification of the XCMT images show that the distribution of void size appears to be the primary difference between the damaged and pristine explosive. Results from the confined SHPB tests show an increase in the true stress from about 3 MPa (unconfined) to 50-80 MPa (aluminum confinement) on the simulant at strain rates of about 500/s; aluminum confinement of the binder increases the stresses achieved from approximately 1 MPa (unconfined) to in excess of 80 MPa. The increase in stress is accompanied by the introduction of axial cracking (similar to ceramics) as a failure mechanism.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 25, 2014
- Accession Number
- ADA607673
Entities
People
- Chad G. Rumchik
- George Sunny
- Jenny Jordan
- John Cox
- Thomas Krawietz
Organizations
- Air Force Research Laboratory