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Highly Porous Microlattices as Ultrathin and Efficient Impact Absorbers

Lai, Chang Quan and Daraio, Chiara (2018) Highly Porous Microlattices as Ultrathin and Efficient Impact Absorbers. International Journal of Impact Engineering, 120 . pp. 138-149. ISSN 0734-743X. http://resolver.caltech.edu/CaltechAUTHORS:20180620-111804620

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Abstract

The deformation and impact energy absorption properties of ultrathin polymeric microlattices were investigated as a function of density, size and positional eccentricity of the trusses, which controlled the amount of bending in the microlattice deformations. We considered highly porous, 3-D microstructures with small lattice constants (≤ 135 μm), and studied their response to high strain rate (∼1000/s) tests, using high speed video capture, SEM imaging and quantitative modelling. The microlattices were found to have excellent impact absorption efficiencies that are 2 - 120 times better than carbon nanotube foams, polycarbonate and silicone rubber, despite being an order of magnitude slimmer than the thinnest commercial foams of similar densities. This high impact absorption efficiency is largely due to the sideways buckling of the microlattice trusses during the crushing stage, which prevented densification of the microlattices at small strains. Furthermore, we showed that varying the positional eccentricity of the trusses and the number of unit cells in the microlattices can modulate their stiffness, strength and energy absorption over an appreciable range, comparable to that obtained through modifications in relative density. Because the microlattices were mostly under stress equilibrium during the impact process, the insights derived from the present study are expected to be valid for quasistatic and low strain rate loadings as well.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1016/j.ijimpeng.2018.05.014DOIArticle
ORCID:
AuthorORCID
Daraio, Chiara0000-0001-5296-4440
Additional Information:© 2018 Elsevier Ltd. Received 20 December 2017, Revised 4 May 2018, Accepted 30 May 2018, Available online 20 June 2018.
Subject Keywords:Auxetic; Negative Poisson's ratio; Microlattice; Impact; Shock; Bending-Dominated; Stretch-Dominated
Record Number:CaltechAUTHORS:20180620-111804620
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20180620-111804620
Official Citation:Chang Quan Lai, Chiara Daraio, Highly porous microlattices as ultrathin and efficient impact absorbers, International Journal of Impact Engineering, Volume 120, 2018, Pages 138-149, ISSN 0734-743X, https://doi.org/10.1016/j.ijimpeng.2018.05.014. (http://www.sciencedirect.com/science/article/pii/S0734743X17311223)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:87260
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:20 Jun 2018 18:48
Last Modified:06 Jul 2018 17:31

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