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Insensitivity to Flaws Leads to Damage Tolerance in Brittle Architected Meta-Materials

Montemayor, L. C. and Wong, W. H. and Zhang, Y.-W. and Greer, J. R. (2016) Insensitivity to Flaws Leads to Damage Tolerance in Brittle Architected Meta-Materials. Scientific Reports, 6 . Art. No. 20570. ISSN 2045-2322. http://resolver.caltech.edu/CaltechAUTHORS:20160208-092709587

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Abstract

Cellular solids are instrumental in creating lightweight, strong, and damage-tolerant engineering materials. By extending feature size down to the nanoscale, we simultaneously exploit the architecture and material size effects to substantially enhance structural integrity of architected meta-materials. We discovered that hollow-tube alumina nanolattices with 3D kagome geometry that contained pre-fabricated flaws always failed at the same load as the pristine specimens when the ratio of notch length (ɑ) to sample width (w) is no greater than 1/3, with no correlation between failure occurring at or away from the notch. Samples with (ɑ/w) > 0.3, and notch length-to-unit cell size ratios of (ɑ/l) > 5.2, failed at a lower peak loads because of the higher sample compliance when fewer unit cells span the intact region. Finite element simulations show that the failure is governed by purely tensile loading for (ɑ/w) < 0.3 for the same (ɑ/l); bending begins to play a significant role in failure as (ɑ/w) increases. This experimental and computational work demonstrates that the discrete-continuum duality of architected structural meta-materials may give rise to their damage tolerance and insensitivity of failure to the presence of flaws even when made entirely of intrinsically brittle materials.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://www.nature.com/articles/srep20570PublisherArticle
http://dx.doi.org/10.1038/srep20570DOIArticle
ORCID:
AuthorORCID
Greer, J. R.0000-0002-9675-1508
Additional Information:© 2016 Macmillan Publishers Limited. This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ received: 04 September 2015. accepted: 06 January 2016. Published: 03 February 2016. The authors gratefully acknowledge the financial support of L.C.M’s National Science Foundation Graduate Research Fellowship and J.R.G’s Defense Advanced Research Projects Agency grant under the MCMA program (contract no. W91CRB-10-0305) and to the National Science Foundation (CMMI‐1234364), as well as Kavli Nanoscience Institute at Caltech for critical support and infrastructure. W.W.H. and Z.Y.W. gratefully acknowledge the financial support from the Agency for Science, Technology and Research (A*STAR), Singapore and the use of computing resources at the A*STAR Computational Resource Centre, Singapore. The authors would also like to acknowledge Tamar Partamian for graphics contributions to Figure 5, Alexander Lozano for helping design the grip and Lucas Meza for help with the CAD images for simulation. The authors would also like to acknowledge Prof. John Hutchinson, Prof. Norman Fleck, and Prof. Katherine Faber for useful discussions.
Group:Kavli Nanoscience Institute
Funders:
Funding AgencyGrant Number
NSF Graduate Research FellowshipUNSPECIFIED
Army Research Office (ARO)W91CRB-10-0305
NSFCMMI‐1234364
Kavli Nanoscience InstituteUNSPECIFIED
Agency for Science, Technology and Research (A*STAR)UNSPECIFIED
Defense Advanced Research Projects Agency (DARPA)UNSPECIFIED
Record Number:CaltechAUTHORS:20160208-092709587
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20160208-092709587
Official Citation:Montemayor, L. C. et al. Insensitivity to Flaws Leads to Damage Tolerance in Brittle Architected Meta-Materials. Sci. Rep. 6, 20570; doi: 10.1038/srep20570 (2016).
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:64294
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:08 Feb 2016 22:17
Last Modified:08 Feb 2016 22:17

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