Embedded Sensing of Microstructural Damage Evolution and Localized Heating in CNT-Nanocomposite Bonded Energetic Materials under Cyclic and Dynamic Loads
Abstract
Instances involving accidental low velocity impact during transportation and handling or tool drop are not uncommon for energetic materials such as propellants and-or explosives. It has been speculated that such seemingly minor mechanical insults can lead to the development of localized regions of high temperature known as ‘hot spots’, i.e. increases in temperature of hundreds of degrees Kelvin which occur on the microscale for short durations. Perhaps of greater concern, such low velocity impact events often result in localized instances of damage within the energetic microstructure which can lead to increased probability of hot spot formation under subsequent cyclic loading due to frictional heating at microcracked surfaces in damaged regions. If the heat generated with hot spot formation is not quickly dissipated, it may lead to ignition of the energetic material and possibly to further stages of detonation, making it extremely important to know what kinds of impact and cyclic loading can trigger hot spot formation. What is needed is a way to monitor microstructural changes in real time during a mechanical insult event, and over the long term due to in service vibration loads via structural health monitoring. Here, we propose to explore the application of piezoresistive nanocomposite binders for real time embedded sensing of strain and damage in energetic materials through a binder-distributed carbon nanotube sensing network in an effort to correlate microstructural features with damage and hot spots. We believe that a fundamental understanding of this process can be achieved through multiscale multiphysics computational modeling and characterization efforts. If successful, we may be able to reduce the stochastic nature of safety characterization and help in designing insult-tolerant, self-sensing energetic materials through increased understanding of impact and cyclic loading induced damage, heating and ignition phenomena as a multiscale process.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 07, 2023
- Source ID
- FA95502110431
Entities
People
- Gary Seidel
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- Virginia Tech