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Accession Number:

AD1122711

Title:

High-Speed, Real-Time Infrared Imaging of Hot Spots in Reactive Materials: Dynamic Experiments and 3D Modeling

Author(s):

Author Organization(s):

Report Date:

2021-02-05

Abstract:

This project consists of two components: (i) design and development of a high speed infrared imaging system and (ii) pressure-shear plate impact experiments on energetic materials (or their simulants). The eventual objective is to combine (i) and (ii) to visualize hot spot evolution in energetic materials under well-defined plane wave loading conditions. Under task (i), we have designed and built a unique high speed infrared imaging system to image temperature fields associated with hotspot evolution in energetic materials under high rate deformation. The system consists of a 24x24 array of HgCdTe detectors that constitutes the focal plane array. We have designed a fan-out chip that provides individual access to each pixel, a flexible printed circuit board to carry the signals to outside the dewar for signal processing, custom optics for diffraction limited imaging and a high speed data-acquisition to acquire images at up to a million frames per second. The progress report on the status of this effort is reported separately. Pressure-shear plate impact (PSPI) experiments were conducted to study the mechanical behavior of HTPB binder and sucrose (energetic material simulant) at high strain rates and high pressures. The main finding of these experiments is that, although HTPB is a soft elastomer at ambient conditions, its shear strength can be as high as 0.5 GPa under a pressure of about 9 GPa and a strain rate of 0.4 x 106 1/s. At similar pressures and shearing rates, PSPI experiments on sucrose--a simulant for energetic crystals--show a shearing resistance of 288 MPa. In these experiments, sucrose exhibits pronounced strain softening, even a dramatic drop in shearing resistance at large shear strains. Pressure-shear plate impact experiments have also been conducted on HTPB-sucrose composite specimens as well.

Pages:

48

File Size:

4.19MB

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SubjectCategory:

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Distribution Statement:

Approved For Public Release

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