Plant materials exhibit a wide range of highly anisotropic mechanical behavior due to a hierarchy of microheterogeneous structures at different length scales. In this article, we present a micromechanics approach that derives a hierarchical microstructure driven model of macroscopic stiffness and strength properties of anisotropic culm materials. As model input, it requires mechanical properties of the base constituents such as cellulose and lignin as well as morphology and volume fractions of all heterogeneous components at each hierarchical level. The latter can be retrieved from imaging data at different length scales, obtained from scanning electron and transmission electron microscopy. We illustrate our modeling approach for the example of bamboo that has gained increasing attention in the last decade due to its role as a sustainable building material. Validating its predictions of macroscopic stiffness moduli and ultimate strength with corresponding experimental measurements, we demonstrate that the micromechanics model provides excellent accuracy without any further phenomenological calibration. We also show that the multiscale modeling approach enables a better physics-based understanding of the origins of bamboo stiffness and strength across different scales.
Bibliographical noteFunding Information:
The first author (T. Gangwar) is partially supported by a Sommerfeld Fellowship awarded by the Department of Civil, Environmental, and Geo- Engineering at the University of Minnesota, which is gratefully acknowledged. The second author (D. Schillinger) gratefully acknowledges support from the Minnesota Department of Agriculture under grant no. 122130 , and from the National Science Foundation via the NSF grant CISE-1565997 and the NSF CAREER award no. 1651577 . The authors also thank Professor Lorna J. Gibson (Massachusetts Institute of Technology), Dr. Jo Heuschele and Professor Kevin P. Smith (Department of Agronomy and Plant Genetics, University of Minnesota) for helpful discussions and comments.
- Bamboo stiffness and strength
- Continuum micromechanics
- Hierarchical multiscale materials
- Plant culm materials