Speaker
Description
Bamboo is characterized by a high growth rate and mechanical properties comparable to those of wood. Therefore, bamboo is of great interest as a sustainable building material while being an efficient CO2 absorber. The material has a hierarchical structure with heterogeneously distributed properties and correspondingly exhibits a strongly anisotropic behaviour [1,2]. Previous research has been investigated the mechanics and the structure of vascular bundles, fiber-like structures present at the mesoscopic scale of the bamboo culm wall. [3,4]. The vascular bundles are composed of a conductive tissue surrounded by sclerenchymatic fibre bundles and are embedded in a matrix of parenchyma cells [1]. However, a profound characterization of the structural and mechanical properties at this scale is not available. In our contribution, computational methods for investigating the statistically inhomogeneous mesostructure and the linear elastic properties of moso bamboo are presented. The mesostructure of the culm wall is characterized using state-of-the-art computational image processing. The characterization process includes the segmentation of cross-section images of the bamboo culm wall, AI-based detection of individual vascular bundles, and a statistical analysis of the image data to derive the characteristics of the structure. In addition to the volume fractions of the fibre bundles and the conductive tissue, characteristics for describing the size, morphology, orientation, and arrangement of the vascular bundles are determined for the first time. This method and the associated characteristics can be applied to any statistically inhomogeneous structure with inclusions. With the structural characteristics at hand, a statistically homogeneous representative volume element of the mesostructure can be reconstructed at any radial position of the wall. With the local linear elastic properties of matrix and fibre bundles given by the literature [3], an FFT-based homogenization model is set up to determine the macroscopic stiffness of the culm wall. This method is used to investigate the anisotropy and inhomogeneity of the material and gives an insight into the local phenomena on a mesoscopic level.
References
[1] W.Lise, The Anatomy of Bamboo Culms, 1998, Vol. 18, 11-208
[2] F. Nogata, H. Takahashi, Intelligent functionally graded material: Bamboo, 1995, Vol. 5.7, 743–751.
[3] P. Dixon, L. Gibson, The structure and mechanics of Moso bamboo material, 2014, Vol. 11.99, 20140321
[4] L. Al-Rukaibawi et al, A numerical anatomy-based modelling of bamboo microstructure, 2021, Vol. 30, 125036
