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In situ diagnostics for a small-bore hypervelocity impact facility

Mihaly, J.M., Tandy, J.D., Adams, M.A., 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) (Access to this publication is currently restricted. You may be able to access a copy if URLs are provided) (KAR id:92321)

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https://doi.org/10.1016/j.ijimpeng.2013.05.004

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 5e7 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 ms). 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 5e7 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 mm-1.7 mm. 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
DOI/Identification number: 10.1016/j.ijimpeng.2013.05.004
Uncontrolled keywords: Hypervelocity impact, High-speed imaging, Debris capture, IR emission, Spectroscopy
Subjects: Q Science > QC Physics
T Technology > TJ Mechanical engineering and machinery
Divisions: Divisions > Division of Natural Sciences > Physics and Astronomy
Depositing User: Jon Tandy
Date Deposited: 01 Mar 2022 21:20 UTC
Last Modified: 02 Mar 2022 09:07 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/92321 (The current URI for this page, for reference purposes)
Tandy, J.D.: https://orcid.org/0000-0002-0772-9182
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