This email is to announce that
Jason Wickham, will be defending his thesis: The Role of Adhesion in the Formation of Hot Spots in Energetic Materials
Thursday, February 11, 2021
at
4:00 PM. The dissertation is directed by Dr. Steve Beaudoin and Dr. Steve Son. The abstract and WebEx info are below, and all are welcome to attend.
The transformation of mechanical energy into thermal energy within composite energetic materials
through various thermomechanical mechanisms is thought to lead to the creation of localized areas of intense heating. The growth of these “hot spots” is responsible for the bulk reaction or decomposition of the energetic material. Understanding the formation
and growth of these hot spots has been an active area of research particularly for high-speed impact and shock conditions, but further work remains to be done in particular with respect to hot spot formation due to periodic mechanical excitation. Previous
literature has established that many potential thermomechanical mechanisms may act at the interface between the constituent components of a composite energetic material. In order to provide further insight and guidance into the design of safer and more resilient
energetic materials, the role of adhesion on hot spot formation for polymer bonded explosives (PBXs), a subset of composite energetic materials, was explored. Single HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocane) crystals in polymer blocks were subjected to
ultrasonic excitation and subsequent heating was captured via infrared thermography. Subsequent testing of HMX PBXs using a drop weight tower captured changes in the sensitivity of the energetic material. Variation of the polymer binder allowed for a range
of adhesive and mechanical properties to be examined. These experiments on the role of adhesion under these kinds of excitations provided insight into how mechanical energy is being transformed into localized heating.
From: Bev Johnson <messenger@webex.com>
Sent: Wednesday, February 10, 2021 11:58 AM
To: Johnson, Beverly J <bevjohnson@purdue.edu>
Subject: (Forward to others) Webex meeting invitation: Wickham Defense
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