Microstructural features influencing the mechanical performance of the Brazil 
nut (Bertholletia excelsa) mesocarp

Sonego, Marilia; Madia, Mauro; Eder, Michaela; Fleck, Claudia; Pessan, Luiz A.

doi:10.1016/j.jmbbm.2020.104306

Item

ITEM ACTIONSEXPORT

Add to Basket

Local TagsRelease HistoryDetailsSummary

Released

Journal Article

Microstructural features influencing the mechanical performance of the Brazil nut (Bertholletia excelsa) mesocarp

MPS-Authors

/persons/resource/persons121255

Eder, Michaela
Michaela Eder, Biomaterialien, Max Planck Institute of Colloids and Interfaces, Max Planck Society;

External Resource

No external resources are shared

Fulltext (restricted access)

There are currently no full texts shared for your IP range.

Fulltext (public)

There are no public fulltexts stored in PuRe

Supplementary Material (public)

There is no public supplementary material available

Citation

Sonego, M., Madia, M., Eder, M., Fleck, C., & Pessan, L. A. (2021). Microstructural features influencing the mechanical performance of the Brazil nut (Bertholletia excelsa) mesocarp. Journal of the Mechanical Behavior of Biomedical Materials, 116: 104306. doi:10.1016/j.jmbbm.2020.104306.

Cite as: https://hdl.handle.net/21.11116/0000-0007-AC23-0

Abstract

Brazil nut (Bertholletia excelsa) fruits are capable of resisting high mechanical forces when released from trees as tall as 50 m, as well as during animal dispersal by sharp-teethed rodents. Thick mesocarp plays a crucial part in seed protection. We investigated the role of microstructure and how sclereids, fibers, and voids affect nutshell performance using compression, tensile and fracture toughness tests. Fractured specimens were analyzed through scanning electron microscopy (SEM) and microtomography (microCT). Mesocarp showed high deformability (strain at max. stress of ∼30) under compression loading, a critical tensile strength of ∼24.9 MPa, a Weibull modulus of ∼3, and an elastic modulus of ∼2 GPa in the tensile test. The fracture toughness, estimated through the work of fracture of SENB tests, reached ∼2 kJ/m². The thick and strong walls of mesocarp cells, with a weaker boundary between them (compound middle lamella), promote a tortuous intercellular crack path. Several toughening mechanisms, such as crack deflection, breaking of fiber bundles, fiber pullout and bridging as well as crack branching, occur depending on how fiber bundles and voids are oriented.