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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. doi:10.1016/j.ijimpeng.2013.05.004.

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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
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URLURL TypeDescription
Rosakis, A. J.0000-0003-0559-0794
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.
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
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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,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42055
Deposited On:24 Oct 2013 23:40
Last Modified:10 Nov 2021 04:37

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