Zakary Wilde

Los Alamos National Laboratory

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Teagan Nakamoto

Los Alamos National Laboratory

Christopher Trujillo

Los Alamos National Laboratory

Douglas Tasker

Los Alamos National Laboratory

John R. Gibson

Los Alamos National Laboratory

Dalton Smith

Los Alamos National Laboratory

Elizabeth Francois

Los Alamos National Laboratory

Pedro Peralta

Arizona State University

Kristina Parrack

Los Alamos National Laboratory

Patrick R. Bowden

Los Alamos National Laboratory

Rylie Lodes

University of Illinois Urbana-Champaign

Cooperative Institutions

Los Alamos National Laboratory

Arizona State University

Purdue University West Lafayette

Argonne National Laboratory

Washington State University

Sandia National Laboratories

Tempe Union High School District

Office of Scientific and Technical Information

United States Department of Energy

National Technical Information Service

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Predicting Hugoniot equation of state in erythritol with ab initio and reactive molecular dynamics

Journal of Applied Physics (2021)

Jing Hu Zakary Wilde Pedro Peralta Christopher L. Muhich Jay Oswald

Erythritol has been proposed as an inert surrogate for developing theoretical and computational models to study aging in energetic materials. In this work, we present a comparison of mechanical and shock properties of erythritol computed using the ReaxFF reactive force field and from ab initio calculations employing density functional theory (DFT). We screened eight different ReaxFF parameterizations, of which the CHO parameters developed for hydrocarbon oxidation provide the most accurate predictions of mechanical properties and the crystal structure of erythritol. Further validation of the applicability of this ReaxFF parameterization for modeling erythritol is demonstrated by comparing predictions of the elastic constants, crystal structure, vibrational density of states, and Hugoniot curves against DFT calculations. The ReaxFF predictions are in close agreement with the DFT simulations for the elastic constants and shock Hugoniot when the crystal is loaded along its c axis but show as much as 30% disagreement in the elastic constants in the ab plane and 12% difference in shock pressures when shocked along the a or b crystal axes. Last, we compare thermomechanical properties predicted from classical molecular dynamics with those calculated using the quasi-harmonic approximation and show that quantum mechanical effects produce large discrepancies in the computed values of heat capacity and thermal expansion coefficients compared with classical assumptions. Combining classical molecular dynamics predictions of mechanical behavior with phonon-based calculations of thermal behaviors, we show that predicted shock-induced temperatures for pressures up to 6.5 GPa do not exceed the pressure-dependent melting point of erythritol.

ReaxFF

Erythritol

10.1063/5.0050716

Cite

Citations (0)

Rogowski coils for studies of detonator initiation and other diagnostics

AIP conference proceedings (2018)

Douglas Tasker Patrick R. Bowden Elizabeth Francois John R. Gibson Teagan Nakamoto

Detonators are fundamental to most explosive systems, yet the detonators themselves are rarely diagnosed to determine how well they function or why they fail. To remedy this, various electrical diagnostics were explored, including: Rogowski coils for high fidelity detection of changes in electrical current in explosive bridgewires and how they relate to detonator performance; and radio frequency (RF) antennas to detect any electromagnetic emissions associated with reaction and growth in the explosives. A new type of Rogowski coil is described and some interesting phenomena were detected with the radio frequency antenna.

Detonator

Klystron

Clipper (electronics)

Thermonuclear Fusion

High fidelity

10.1063/1.5045027

Cite

Citations (3)

Probing detonator performance through radio wave emissions

AIP conference proceedings (2018)

Zakary Wilde John R. Gibson Teagan Nakamoto Dalton Smith Douglas Tasker

Experiments were performed using a copper antenna to observe transient electric fields generated by shocked Pentaerythritol Tetranitrate (PETN), which behaves as a piezoelectric explosive. PETN pellets were shocked using a detonator and polyvinyl chloride (PVC) as shock attenuation. The amount of attenuation was varied until an initiation threshold was found to increase the probability of a deflagration-to-detonation (DDT) transition occurring. These experiments showed distinct transient shifts in frequency over the duration of the experiments. Correlation was observed between certain shifts in frequency and if the PETN pellet detonated.

Pentaerythritol tetranitrate

Detonator

Deflagration

Transient (computer programming)

10.1063/1.5045030

Cite

Citations (1)

Investigation of Meso-Erythritol as an inert shock surrogate for PETN shock experiments

AIP conference proceedings (2020)

Zakary Wilde Tyler Eastmond Kirk Bohlen Pedro Peralta

Inert surrogates for high explosives provide low-risk options to study their basic material response to extreme conditions such as high pressure and high strain rates. Meso-Erythritol is under evaluation as a shock surrogate for Pentaerythritol Tetranitrate (PETN) due to their similar density, crystal structures, and melting points. However, no Hugoniot data for Meso-Erythritol currently exists. Preliminary gas gun experiments were performed to test a setup for determining the Hugoniot of Meso-Erythritol as a powder compact at 1.18 g/cc (82% theoretical maximum density). Photon doppler velocimetry was used to measure particle velocities. Experiments investigated impact velocities of up to 450 meters per second, and the testing conditions were used to inform hydrocode simulations. Initial results suggest that the resulting particle velocity in Meso-Erythritol is lower than PETN when compared to hydrocode simulations and that shock decay in Meso-Erythritol is faster than PETN.

Erythritol

Pentaerythritol tetranitrate

Particle (ecology)

Inert

10.1063/12.0000901

Cite

Citations (1)

Fireset and Cable Design for Support of Detonator Diagnostic Development

Bulletin of the American Physical Society (2017)

Christopher Trujillo Elizabeth Francois John R. Gibson Rylie Lodes Teagan Nakamoto

Detonator

Source

Cite

Citations (0)

Development of New Diagnostics for Detonator Characterization

OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) (2017)

Teagan Nakamoto Elizabeth Francois John R. Gibson Dalton Smith Douglas Tasker

Detonator

Characterization

Source

Cite

Citations (0)

The Correlation of Electrical Fields and Detonator Behavior

Bulletin of the American Physical Society (2017)

Zakary Wilde Elizabeth Francois John R. Gibson Rylie Lodes Teagan Nakamoto

Detonator

Source

Cite

Citations (0)

A Thermal and Nanomechanical Study of Molecular Crystals as Versatile Mocks for Pentaerythritol Tetranitrate

Crystals (2020)

Alexandra C. Burch Zakary Wilde David F. Bahr John D. Yeager

Pentaerythritol tetranitrate (PETN) is a commonly used high explosive (HE) in detonators. Often, surrogate or “mock” materials are used in place of HE for mechanical tests, proofing out equipment, or developing new diagnostics. However, there is no commonly accepted mock for PETN. A good mock should match at least one physical property of the target material, and ideally mimic multiple thermal and mechanical properties. Here, we investigate several molecular crystals to evaluate their efficacy in mocking PETN density, melting point, elastic modulus, hardness, plastic deformation, and fracture behavior. Materials were tested with a combination of calorimetry and nanoindentation. Two materials, 2,4,6-trifluorobenzoic acid (246 TFBA) and mesoerythritol, were downselected for detailed indentation study after the initial round of screening experiments, both were found to mimic PETN mechanical behavior quite well, 246 TFBA closer to PETN in most properties (hardness, modulus, and density) than erythritol, but erythritol having advantages in relative cost and matching the onset of yield. Depending on the desired implementation of the mock, one material may be preferred over the other, but both have potential as generic mocks for PETN. Nanoindentation is demonstrated as a versatile tool to provide rapid screening of these materials’ mechanical properties.

Pentaerythritol tetranitrate

Energetic material

Indentation

10.3390/cryst10020126

Cite

Citations (8)

Rogowski coils for studies of detonator initiation and other diagnostics

OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) (2017)

Douglas Tasker Patrick R. Bowden Elizabeth Francois John R. Gibson Teagan Nakamoto

Detonator

10.1063/1.5045027

Cite

Citations (0)

Novel uses of detonator diagnostics

John R. Gibson Zakary Wilde Douglas Tasker Elizabeth Francois Teagan Nakamoto

A novel combination of diagnostics is being used to research the physics of detonator initiation. The explosive PETN (Pentaerythritol tetranitrate) commonly used in detonators, is also a piezo-electric material that, when sufficiently shocked, emits an electromagnetic field in the radio frequency (RF) range, along crystal fracture planes. In an effort to capture this RF signal, a new diagnostic was created. A copper foil, used as an RF antenna, was wrapped around a foam fixture encompassing a PETN pellet. Rogowski coils were used to obtain the change in current with respect to time (di/dt) the detonator circuit, in and polyvinylidene difluoride (PVDF) stress sensors were used to capture shockwave arrival time. The goal of these experiments is to use these diagnostics to study the reaction response of a PETN pellet of known particle size to shock loading with various diagnostics including an antenna to capture RF emissions. Our hypothesis is that RF feedback may signify the rate of deflagration to detonation transition (DDT) or lack thereof. The new diagnostics and methods will be used to determine the timing of start of current, bridge burst, detonator breakout timing and RF generated from detonation. These data will be compared to those of currently used diagnostics in order to validate the accuracy of these new methods. Future experiments will incorporate other methods of validation including dynamic radiography, optical initiation and use of magnetic field sensors.

Detonator

Pentaerythritol tetranitrate

10.2172/1392861

Cite

Citations (0)