Influence of the cross-linking of the cellulosic fibrillar network on the effective hygro-mechanical behaviour of the wood cell wall (vol 233, pg 4985, 2022)

This study aims to analyze the influence of the fibrils oscillations and connections on the effective hygro-elastic behavior of the wood cell wall. For that, two different models of microstructure describing the cell wall are introduced: the model 1S, for which the fibrils are allowed to oscillate in one direction like a sine curve, and the model 2S, for which the fibrils oscillate in two directions as a helix. The effective hygro-elastic behavior of the cell wall associated with each of the two models is computed by numerical periodic homogenization. Then, we analyze the effects of the fibers oscillations on the effective behavior by making varying some parameters such as the shape ratio of the unit cell, the fibrils volume fraction, or the elastic contrast between the matrix and the fibrils. It is shown that the fibrils oscillations have a significant effect on some effective moduli of the cell wall, such as the effective shear moduli (G) over tilde (12) (for both model 1S and 2S) and (G) over tilde (13), (G) over tilde (23) (for model 2S only).