Title: High speed X-ray phase contrast imaging of energetic composites under dynamic compression

Abstract

Fracture of crystals and subsequent frictional heating are associated with formation of hot spots in energetic composites such as polymer bonded explosives (PBXs). Traditional high speed optical imaging methods cannot be used to study the dynamic sub-surface deformation and fracture behavior of such materials due to their opaque nature. In this study, high speed synchrotron X-ray experiments are conducted to visualize the in situ deformation and fracture mechanisms in PBXs manufactured using octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) crystals and hydroxyl-terminated polybutadiene (HTPB) binder. A modified Kolsky bar apparatus was used to apply controlled dynamic compression on the PBX specimens, and a high speed synchrotron X-ray phase contrast imaging (PCI) setup was used to record the in situ deformation and failure in the specimens. The experiments show that synchrotron X-ray PCI provides a sufficient contrast between the HMX crystals and the doped binder, even at ultrafast recording rates. Under dynamic compression, most of the cracking in the crystals was observed to be due to the tensile stress generated by the diametral compression applied from the contacts between the crystals. Tensile stress driven cracking was also observed for some of the crystals due to the transverse deformation of the binder and superior bonding between themore » crystal and the binder. In conclusion, the obtained results are vital to develop improved understanding and to validate the macroscopic and mesoscopic numerical models for energetic composites so that eventually hot spot formation can be predicted.« less

Authors:

Parab, Niranjan D.  ^[1];

• Search DOE PAGES for author "Parab, Niranjan D."
• Search DOE PAGES for ORCID "0000-0002-3215-1466"

Roberts, Zane A. ^[1]; Harr, Michael H.  ^[1];

• Search DOE PAGES for author "Harr, Michael H."
• Search DOE PAGES for ORCID "0000-0002-9154-6038"

Mares, Jesus O. ^[1]; Casey, Alex D. ^[1]; Gunduz, I. Emre ^[1]; Hudspeth, Matthew ^[1]; Claus, Benjamin ^[1]; Sun, Tao ^[2]; Fezzaa, Kamel ^[2]; Son, Steven F.  ^[1];

• Search DOE PAGES for author "Son, Steven F."
• Search DOE PAGES for ORCID "0000-0001-7498-2922"

Chen, Weinong W. ^[1]

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+ Show Author Affiliations

1. Purdue Univ., West Lafayette, IN (United States)
2. Argonne National Lab. (ANL), Argonne, IL (United States)

Publication Date:

Mon Sep 26 00:00:00 EDT 2016

Research Org.:

Argonne National Laboratory (ANL), Argonne, IL (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); Air Force Research Laboratory (AFRL), Air Force Office of Scientific Research (AFOSR)

OSTI Identifier:

1373758

Alternate Identifier(s):

OSTI ID: 1328567

Grant/Contract Number:  

AC02-06CH11357

Resource Type:

Accepted Manuscript

Journal Name:

Applied Physics Letters

Additional Journal Information:

Journal Volume: 109; Journal Issue: 13; Journal ID: ISSN 0003-6951

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE