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Journal article
Microstructural design for mechanical-optical multifunctionality in the exoskeleton of the flower beetle Torynorrhina flammea
Proceedings of the National Academy of Sciences - PNAS, v 118(25)
22 Jun 2021
PMID: 34140412
Abstract
Biological systems have a remarkable capability of synthesizing multifunctional materials that are adapted for specific physiological and ecological needs. When exploring structure-function relationships related to multifunctionality in nature, it can be a challenging task to address performance synergies, trade-offs, and the relative importance of different functions in biological materials, which, in turn, can hinder our ability to successfully develop their synthetic bioinspired counterparts. Here, we investigate such relationships between the mechanical and optical properties in a multifunctional biological material found in the highly protective yet conspicuously colored exoskeleton of the flower beetle, Torynorrhina flammea. Combining experimental, computational, and theoretical approaches, we demonstrate that a micropillar-reinforced photonic multilayer in the beetle's exoskeleton simultaneously enhances mechanical robustness and optical appearance, giving rise to optical damage tolerance. Compared with plain multilayer structures, stiffer vertical micropillars increase stiffness and elastic recovery, restrain the formation of shear bands, and enhance delamination resistance. The micropillars also scatter the reflected light at larger polar angles, enhancing the first optical diffraction order, which makes the reflected color visible from a wider range of viewing angles. The synergistic effect of the improved angular reflectivity and damage localization capability contributes to the optical damage tolerance. Our systematic structural analysis of T. flammea's different color polymorphs and parametric optical and mechanical modeling further suggest that the beetle's microarchitecture is optimized toward maximizing the first-order optical diffraction rather than its mechanical stiffness. These findings shed light on material-level design strategies utilized in biological systems for achieving multifunctionality and could thus inform bioinspired material innovations.
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Details
- Title
- Microstructural design for mechanical-optical multifunctionality in the exoskeleton of the flower beetle Torynorrhina flammea
- Creators
- Zian Jia - Virginia TechMatheus C. Fernandes - Harvard University ,Zhifei Deng - Virginia TechTing Yang - Virginia TechQiuting Zhang - North Carolina State UniversityAlfie Lethbridge - Univ Exeter, Sch Phys, Exeter EX4 4QL, Devon, EnglandJie Yin - North Carolina State UniversityJae-Hwang Lee - University of Massachusetts AmherstLin Han - Drexel UniversityJames C. Weaver - Harvard University ,Katia Bertoldi - Harvard University ,Joanna Aizenberg - Harvard University ,Mathias Kolle - Massachusetts Institute of TechnologyPete Vukusic - Univ Exeter, Sch Phys, Exeter EX4 4QL, Devon, EnglandLing Li - Virginia Tech
- Publication Details
- Proceedings of the National Academy of Sciences - PNAS, v 118(25)
- Publisher
- Natl Acad Sciences
- Number of pages
- 9
- Grant note
- DMREF-1922321 / NSF; National Science Foundation (NSF) DGE-1144152 / NSF Graduate Research Fellowships Program Fellowship Grant Department of Mechanical Engineering at Virginia Polytechnic Institute and State University
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- School of Biomedical Engineering, Science, and Health Systems
- Web of Science ID
- WOS:000672806300011
- Scopus ID
- 2-s2.0-85108367120
- Other Identifier
- 991019168314504721
InCites Highlights
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- Collaboration types
- Domestic collaboration
- International collaboration
- Web of Science research areas
- Multidisciplinary Sciences