Using In Situ Synchrotron‐Radiation‐Based Microtomography to Investigate 3D Structure‐Dependent Material Properties of Tension Wood

• Published in: Advanced engineering materials Vol. 23; no. 11
• Main Authors: Schmelzle, Sebastian, Bruns, Stefan, Beckmann, Felix, Moosmann, Julian, Lautner, Silke
• Format: Journal Article
• Language: English
• Published: 01.11.2021
• Subjects: digital volume correlation; load frame; mechanical testing; synchrotron-radiation-based microtomography; wood
• ISSN: 1438-1656; 1527-2648
• DOI: 10.1002/adem.202100235

Synchrotron‐radiation‐based microtomography enables the 3D analysis of biological samples in situ beyond simple visualization, providing accurate measurements and recording of temporal data. The microtomography end station at P05 (PETRA III, Hamburg, Germany), operated by the Helmholtz Zentrum Hereon, can accommodate complex sample environments such as a load frame for mechanical testing. Herein, the strain analysis of a volumetric time series dataset of small hardwood samples is presented. For this in situ mechanical testing, the load frame is operated in tensile mode, and the biogenic material samples are subdivided into those specialized for tensile forces and those of regular anatomical structure. Digital volume correlation analysis allows for the prediction of strain development at any position in the sample. The tissue specialized for tensile strength can align dislocations formed under tension such that the deformation is stronger and more ordered. The results show how high‐resolution imaging of sequential loading and the subsequent localization of strain can reveal functional morphological relationships. These methods can be extended to other biological materials and may prove to be extremely relevant for the analyses of fibrous and/or layered composite materials. The 3D effects of tensile load on wood are traced in situ. The results can be attributed to the characteristics of the respective tissues and extended beyond the simple visual analysis of evident deformations. The calculated stress effects allow for the early prediction of stress development at any position in the specimen.