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In situ diagnostics for a small-bore hypervelocity impact facility

Mihaly, J. M. and Tandy, J. D. and Adams, M. A. and Rosakis, A. J. (2013) In situ diagnostics for a small-bore hypervelocity impact facility. International Journal of Impact Engineering, 62 . pp. 13-26. ISSN 0734-743X. http://resolver.caltech.edu/CaltechAUTHORS:20131024-152446516

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Abstract

New in situ diagnostic capabilities and improvements made to the previously reported 1.8 mm bore, two-stage light-gas gun facility located at the California Institute of Technology are described. The Small Particle Hypervelocity Impact Range (SPHIR) facility is capable of routinely producing launch speeds of 5–7 km/s for launch package masses < 6 mg, with maximum speeds exceeding 10 km/s. The facility features a comprehensive ensemble of in situ diagnostics that are available for simultaneous implementation in every impact experiment. A fast (150,000 fps) camera is used routinely to provide impactor velocimetry. A gated, intensified ultra-high-speed camera is used in conjunction with an optical technique to create shadowgraph images of hypervelocity impact phenomena with very short exposure times (25 ns) and inter-frame times (<1 μs). This technique uses a constant 532 nm wavelength laser to deliver a collimated, coherent illumination beam orthogonal to the projectile flight direction that provides a 100 mm diameter maximum field of view. The ultra-high-speed camera produces 8 images with exposure and inter-frame times sufficiently short to enable sharp visualization of impact features with little motion blur at the test speeds of 5–7 km/s. Additionally, a debris capture system is located behind the target configuration during every experiment. This system is composed of layers of closed-cell foam and plastic film and provides depth of penetration and trajectory measurement for debris particles thrown behind the target. Lastly, the SPHIR facility utilizes two additional high-speed cameras coupled with two spectrographs to characterize the light emitted by the impact event. One spectrograph and its high-speed camera records UV–visible emission spectra in the wavelength range between 300 nm and 850 nm. The other spectrograph uses a high-speed, infrared camera to capture a single full-field image of the near-IR emission in the wavelength range of 0.9 μm–1.7 μm. These two spectrograph camera systems provide both visual and spectral data of the hypervelocity impact emission; yielding information regarding the molecular composition of both the impact ejecta and debris. The extensive diagnostic capabilities and techniques described can be used with a wide variety of impactors, target materials and target configurations to address a wide variety of engineering and scientific problems.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1016/j.ijimpeng.2013.05.004DOIArticle
http://www.sciencedirect.com/science/article/pii/S0734743X13001103PublisherArticle
Additional Information:© 2013 Elsevier Ltd. Received 30 January 2013; Received in revised form 23 April 2013; Accepted 21 May 2013; Available online 31 May 2013. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-FC52-08NA28613. The authors would also like to thank Mike Mello for his assistance with the opto-mechanical design of the LSL system, Petros Arakelian for his assistance in installing the optical benches and safety features, and Phillip Ou for compiling the capture pack data.
Group:GALCIT
Funders:
Funding AgencyGrant Number
Department of Energy (DOE) National Nuclear Security AdministrationDE-FC52-08NA28613
Subject Keywords:Hypervelocity impact; High-speed imaging; Debris capture; IR emission; Spectroscopy
Record Number:CaltechAUTHORS:20131024-152446516
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20131024-152446516
Official Citation:J.M. Mihaly, J.D. Tandy, M.A. Adams, A.J. Rosakis, In situ diagnostics for a small-bore hypervelocity impact facility, International Journal of Impact Engineering, Volume 62, December 2013, Pages 13-26, ISSN 0734-743X, http://dx.doi.org/10.1016/j.ijimpeng.2013.05.004.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42055
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:24 Oct 2013 23:40
Last Modified:20 Sep 2016 23:13

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