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3D optical diagnostics for explosively driven deformation and fragmentation

International Journal of Impact Engineering

Guildenbecher, Daniel R.; Jones, Elizabeth M.; Munz, Elise D.; Reu, Phillip L.; Miller, Timothy J.; Perez, Francisco; Thompson, Andrew D.; Ball, James P.

High-speed, optical imaging diagnostics are presented for three-dimensional (3D) quantification of explosively driven metal fragmentation. At early times after detonation, Digital Image Correlation (DIC) provides non-contact measures of 3D case velocities, strains, and strain rates, while a proposed stereo imaging configuration quantifies in-flight fragment masses and velocities at later times. Experiments are performed using commercially obtained RP-80 detonators from Teledyne RISI, which are shown to create a reproducible fragment field at the benchtop scale. DIC measurements are compared with 3D simulations, which have been ‘leveled’ to match the spatial resolution of DIC. Results demonstrate improved ability to identify predicted quantities-of-interest that fall outside of measurement uncertainty and shot-to-shot variability. Similarly, video measures of fragment trajectories and masses allow rapid experimental repetition and provide correlated fragment size-velocity measurements. Measured and simulated fragment mass distributions are shown to agree within confidence bounds, while some statistically meaningful differences are observed between the measured and predicted conditionally averaged fragment velocities. Together these techniques demonstrate new opportunities to improve future model validation.

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TYPE Journal Article YEAR 2022
DOIOSTIScopus

Critical detonation thickness in vapor-deposited pentaerythritol tetranitrate (PETN) films

AIP Conference Proceedings

Tappan, Alexander S.; Knepper, Robert; Wixom, Ryan R.; Marquez, Michael P.; Ball, James P.; Miller, Jill C.

The use of physical vapor deposition is an attractive technique to produce microenergetic samples to study sub-millimeter explosive behavior. Films of the high explosive PETN (pentaerythritol tetranitrate) were deposited through vacuum thermal sublimation. Deposition conditions were varied to understand the effect of substrate cooling capacity and substrate temperature during deposition. PETN films were characterized with surface profilometry and scanning electron microscopy. Detonation velocity versus PETN film thickness was analyzed using a variation of the standard form for analysis of the diameter effect. Results were compared with previous work conducted on PETN films deposited with lower substrate cooling capacity. Seemingly subtle variations in PETN deposition conditions led to differences in detonation behaviors such as critical thickness for detonation, detonation velocity at "infinite" thickness, and the shape of the critical thickness curves. © 2012 American Institute of Physics.

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TYPE Conference YEAR 2012
OSTIScopus
Results 1–25 of 27
Results 1–25 of 27