Proceedings Paper for the 59th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference at AIAA SciTech 2019 San Diego, California, USA 7 - 11 January 2019

AIAA 2019-0962

Detecting “Hot-Spot” Damage in Granular Energetics Using a Thermo-electromechanical Peridynamics Model

Stefan Povolny, Krishna Kiran Talamadupula, Naveen Prakash and Gary D. Seidel
Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061-0203, USA

Polymer-bonded explosive (PBX)-based munitions have been shown to adversely respond to damaging stimuli, such as accidental low-velocity impact during transportation and handling or tool drop [1, 2]. Specifically, it has been experimentally confirmed that such damage may lead to the formation of hot spots [3]. These are small zones that develop in damaged areas of the material where the temperature becomes significantly elevated, i.e. hundreds of Kelvin [3]. If not quickly dissipated, this increase in temperature could increase the possibility of accidental detonation. In addition, while it is clear that the damage is the cause of hot spot formation, the mechanism through which this happens is poorly understood. To address these concerns, a computational model based on thermo-electromechanical peridynamic theory is developed and used to investigate how various types of damage lead to hot spot formation. Furthermore, it is demonstrated that functionalization of the polymer binder via the addition of carbon nanotubes (CNTs) enables detection and risk assessment of hot spots, in addition to strain sensing. This 3 phase composite of CNTs, polymer binder and energetic grains is studied under the term Nanocomposite Bonded Explosives (NCBXs). A multifunctional thermo-electromechanical peridynamic model is proposed in this study including piezoresistive strain sensing and a new frictional heat generation model to analyze the thermo-electromechanical response of these NCBX materials under impact loading conditions.