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Metamaterials with engineered failure load and stiffness

Injeti, Sai Sharan and Daraio, Chiara and Bhattacharya, Kaushik (2019) Metamaterials with engineered failure load and stiffness. Proceedings of the National Academy of Sciences of the United States of America, 116 (48). pp. 23960-23965. ISSN 0027-8424. PMCID PMC6883817.

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Architected materials or metamaterials have proved to be a very effective way of making materials with unusual mechanical properties. For example, by designing the mesoscale geometry of architected materials, it is possible to obtain extremely high stiffness-to-weight ratio or unusual Poisson’s ratio. However, much of this work has focused on designing properties like stiffness and density, and much remains unknown about the critical load to failure. This is the focus of the current work. We show that the addition of local internal prestress in selected regions of architected materials enables the design of materials where the critical load to failure can be optimized independently from the density and/or quasistatic stiffness. We propose a method to optimize the specific load to failure and specific stiffness using sensitivity analysis and derive the maximum bounds on the attainable properties. We demonstrate the method in a 2D triangular lattice and a 3D octahedral truss, showing excellent agreement between experimental and theoretical results. The method can be used to design materials with predetermined fracture load, failure location, and fracture paths.

Item Type:Article
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URLURL TypeDescription Information CentralArticle
Daraio, Chiara0000-0001-5296-4440
Bhattacharya, Kaushik0000-0003-2908-5469
Additional Information:© 2019 National Academy of Sciences. Published under the PNAS license. Edited by David A. Weitz, Harvard University, Cambridge, MA, and approved October 21, 2019 (received for review July 9, 2019). PNAS first published November 11, 2019. Data Availability: All data needed to evaluate the conclusions in this paper are available in the main text or in SI Appendix. We thank Petros Arakelian for helping print the samples used for this research. We also thank Connor McMahan and Dr. Osama Bilal for useful discussions on the experiments. This work was supported by the Shang-Li and Betty Huang endowed graduate fellowship fund in mechanical engineering at the California Institute of Technology. C.D. acknowledges support from the National Science Foundation (NSF) CSSI Grant 1835735. Author contributions: S.S.I., C.D., and K.B. designed research; S.S.I. performed research; S.S.I., C.D., and K.B. contributed new reagents/analytic tools; S.S.I., C.D., and K.B. analyzed data; and S.S.I., C.D., and K.B. wrote the paper. The authors declare no competing interest. This article is a PNAS Direct Submission. This article contains supporting information online at
Funding AgencyGrant Number
Subject Keywords:metamaterials; lattices; architected structures; failure; optimal properties
Issue or Number:48
PubMed Central ID:PMC6883817
Record Number:CaltechAUTHORS:20191111-154114590
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Official Citation:Metamaterials with engineered failure load and stiffness Sai Sharan Injeti, Chiara Daraio, Kaushik Bhattacharya Proceedings of the National Academy of Sciences Nov 2019, 116 (48) 23960-23965; DOI: 10.1073/pnas.1911535116
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:99786
Deposited By: Tony Diaz
Deposited On:12 Nov 2019 16:09
Last Modified:16 Apr 2020 20:53

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