Bulletin of the American Physical Society
21st Biennial Conference of the APS Topical Group on Shock Compression of Condensed Matter
Volume 64, Number 8
Sunday–Friday, June 16–21, 2019; Portland, Oregon
Session E1: DSIC: Detonators |
Hide Abstracts |
Chair: Elizabeth Lee, AWE Room: Grand Ballroom I |
Monday, June 17, 2019 3:30PM - 3:45PM |
E1.00001: Capacitive Sensing of a Detonation Wave's Reaction Zone James Edgeley, Chris Braithwaite Novel sensors have been developed to measure the position and thickness of the conducting zone of a detonation wave in a low density pressing of pentaerythritol tetranitrate (PETN). The sensors employ the phenomenon of capacitive sensing, whereby a change in the conductivity of the surroundings induces a change in the capacitance between two electrodes. The conductivity zone is used as a proxy to indicate where reaction is occurring. A fibre-coupled laser flyer system is used to initiate the detonation. [Preview Abstract] |
Monday, June 17, 2019 3:45PM - 4:00PM |
E1.00002: The Effect of Surface Area and Density on the Volumetric Shock Initiation of PETN Rosemary Burritt, Micael Bowden A volumetric shock initiation criterion, based on the concept of a critical shock volume as a function of shock pressure, has been shown to describe the initiation of PETN and HNS by curved, thin flyers. Historic criteria based upon a shock duration cannot describe this process as completely. Data is often only available, for a given material, for a single density and surface area. Therefore, the effect of density and surface area on the pressure/volume relationship is not well known, though may be hypothesized. PETN of two different surfaces, at two different densities, was initiated with electrically-driven plastic flyer plates of a range of thicknesses and diameters, and the pressure required for initiation determined. This data, along with comparison to published data, allows for the effect of density and surface to be quantified. Increasing the surface area, and decreasing the density, was found to increase the shock sensitivity. These effects were found to be more pronounced for small volume shocks, such as those generated by LEEFIs. For larger flyers, the effect was less pronounced. [Preview Abstract] |
Monday, June 17, 2019 4:00PM - 4:15PM |
E1.00003: Effect of metallic foil thickness distribution on energy deposition during its electrical exploding Fan Lei, Qiubo Fu Exploding Foil initiator (EFI) refers to the rapid heating, melting, vaporization and ionization processes of metallic foil driven by high pulsed current. It is widely used in accelerating plastic slappers for high pressure experiments or igniting energetic materials safely and efficiently. The thickness distribution of the metallic foil will strongly effect the energy deposition on the foil. In order to confirm this point, a series of EFI test are conducted by changing the Bridge (narrow part) and Ground (wide part) thickness of the foil. The experimental setup is revealed in figure 1.The electrical energy is firstly stored in a capacitance, and after the high-voltage switch is triggered the current of RLC circuit starts to grow. The maximum current reaches several kA causing the rapid heating of the foil. The current I(t) and voltage U(t) are record by a oscilloscope. By applying suitable time-varied inductance L(t), a 2-D simulation code is developed to simulate the current and voltage curves of the foil and gives the temperature and energy distribution on the foil during its rapid heating. The experimental and simulated result both indicate that the electrical energy more likely deposits in the thin or corner areas. This research provides a way to control the energy distribution and builds up a simulation code to help us understand the mechanism of the foil exploding. \begin{figure}[htbp] \centerline{\includegraphics[width=3.56in,height=2.00in]{260220191.eps}} \label{fig1} \end{figure} \begin{center} Figure 1. the schematic diagram of the EFIs experimental system. \end{center} [Preview Abstract] |
Monday, June 17, 2019 4:15PM - 4:30PM |
E1.00004: Initiation Studies on Exploding Bridgewires and Spark Gaps Nathaniel Sanchez, Will Neal, Doug McHugh, Brian Jensen The exploding bridgewire detonator has been studied extensively since its invention in the 1940's, however details of the initiation mechanism are still not fully understood. This is further complicated with spark gap initiation devices. Recent advances in diagnostics coupled with synchrotron sources have allowed the in-situ investigation of bridgewires and interactions with porous media. This work utilizes Phase Contrast X-ray imaging (PCI) at the Advanced Photon Source (APS) to dynamically image bridgewire burst and the subsequent events leading towards initiation. This data coupled with the magnetohydrodynamic code Alegra, have led towards a better understanding of the complex initiation mechanism pathways that exist for various configurations. [Preview Abstract] |
(Author Not Attending)
|
E1.00005: Shock Waves Formed by the Geometric Characteristics of Exploding Metal Wires William Neal, Nate Sanchez Many of the models describing the explosion of metal wires rely upon the assumption that the wire explodes as a bulk, i.e.: the entire length of the wire explodes simultaneously. This study demonstrates that this is not the case within the typical energy regime used to fire exploding bridgewire (EBW) detonators. A mixture of high-resolution x-ray phase contrast radiographs and 3-dimensional magneto-hydrodynamic simulations are presented in order to shed light on mechanisms comprising the explosion of EBWs as the capacitor discharge unit (CDU) voltage is increased from the V50 threshold to all-fire. The second-order effects of wire geometry on shock-pressure, and bulk electrical resistivity, are discussed in this study. In addition, observations are presented that help describe the energy transfer mechanisms that cause explosive initiation within EBW detonators. [Preview Abstract] |
Monday, June 17, 2019 4:45PM - 5:00PM |
E1.00006: High-Throughput Initiation: Flyer and Thin-Film Explosive Characterization Alexander Tappan, Robert Knepper, Samuel D. Park, Randal Schmitt, Stephen Rupper, Johnathan Vasiliauskas, Caitlin H. O'Grady, Shawn C. Stacy, Michael P. Marquez Experiments on explosive initiation are important for generating reactive burn modeling parameters yet can be expensive and time-consuming. We present a novel framework for high-throughput testing of explosives based on the well-known microplate standard, which is ubiquitous in the biological sciences. This framework uses a laser-driven flyer similar to that used in numerous laboratories. Experiments on explosive initiation using vapor-deposited explosive samples on transparent substrates using the 96-well microplate standard are presented. These samples are characterized with optical microscopy, stylus profilometry, and scanning electron microscopy. Initiation experiments are performed in the 96-well configuration using laser-driven flyers and photonic Doppler velocimetry. Flyer characterization and shock initiation data are presented. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700