Nanomechanical testing of energetic materials to quantify and rank sensitivity
Abstract
When promising new energetic material compounds are created there is a need to perform phenomenological drop-weight impact tests and friction tests for determining sensitivity to shock and initiation of an energetic reaction (the “H50” sensitivity criteria). This leads to the need to create significant volumes of materials for this testing. Historically, predictions of sensitivity are based on molecular structure, but there may be factors of 5 differences in experimentally measured sensitivity between materials that are chemically similar but crystalize in different structures. Of the many new compounds that are prepared, relatively few are subsequently prepared at a scale to begin more scientific tests to assess their safety properties. The research objective of this study is to use nanomechanical testing to experimentally examine plasticity in sub-mm crystals of energetic materials, and determine if the propensity for measurable plastic deformation correlates with the H50 sensitivity. The specific technical approach will be to use nanoindentation to assess the hardness and the onset of plastic deformation in four energetic materials. Los Alamos National Laboratory will provide samples of the energetic materials in sub-mm form that exhibit providing a range of H50 sensitivities from ~12 to >320cm. The anticipated outcome of the work will be to determine if this nanoscale test on real-world energetic materials in the form in which they are used (small, sub-mm crystals) makes a direct or scalable relationship between plastic deformation performance and H50 sensitivity. Prior work on cm-sized crystalline energetics suggests that plasticity should track with sensitivity; however this has never been validated on crystals in conventionally processed forms. If successful, this work will impact the field by providing a safe and rapid assessment method allowing for screening new energetic materials without the need for fabricating large quantities used for drop-weight tests.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 24, 2016
- Source ID
- FA95501610101
Entities
People
- David F Bahr
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Virginia