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Published April 2015 | Supplemental Material
Journal Article Open

Shock formation and rate effects in impacted carbon nanotube foams


We investigate rate-effects in the dynamic response of vertically aligned carbon nanotube (VACNT) foams excited by impacts at controlled velocities. They exhibit a complex rate-dependent loading–unloading response at low impact velocities and they support shock formation beyond a critical velocity. The measured critical velocities are ∼10 times lower than in other foams of similar densities—a desirable characteristic in impact protective applications. In-situ high-speed microscopy reveals strain localization and progressive buckling at low velocities and a crush-front propagation during shock compression. We correlate these responses to quantitative measurements of the density gradient and fiber morphology, obtained with spatially resolved X-ray scattering and mass attenuation.

Additional Information

© 2014 Elsevier Ltd. Received 21 August 2014. Accepted 1 December 2014. Available online 5 December 2014. We thank Ludovica Lattanzi and Wei-Hsun Lin for assistance in preparing the educational video, Jan Rys (ETH Zurich) and Darwin Zwissler (UC Berkeley, USA) for assistance during experiments. We acknowledge financial support from the Institute for Collaborative Biotechnologies (ICB) under the contract W911NF-09-D-0001 with the Army Research Office (ARO). A portion of this work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-7NA27344. X-ray characterization was performed at beamline 7.3.3 at the Advanced Light Source, which is supported by the Director, Office of Science, and Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

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Supplemental Material - mmc3.mp4

Supplemental Material - mmc4.mp4


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