Analysis of creep and modulus loss of the wood cell wall

作者：Pan, Yihui; Zhong, Zheng^*

来源：Acta Mechanica, 2016, 227(11): 3191-3203.

DOI：10.1007/s00707-015-1532-y

• HYPERELASTIC CONSTITUTIVE MODEL
• FIBER-REINFORCED COMPOSITES
• NONLINEARLY ELASTIC SOLIDS
• HUMAN ANNULUS FIBROSUS
• MOISTURE ABSORPTION
• MECHANICAL DEGRADATION
• POLYPROPYLENE COMPOSITES
• SHEAR INTERACTION
• LARGE-DEFORMATION
• BEHAVIOR

This paper proposes a nonlinear constitutive model for the wood cell wall based on the nonequilibrium thermodynamics. The wood cell wall is modeled as a long fiber-reinforced composite with cellulose microfibril enclosed by hemicellulose and lignin. An internal variable is introduced into the Helmholtz free energy of the cell wall system, to describe the modulus loss of hemicellulose due to moisture absorption. The viscoelastic behavior of the wood cell wall changes with its moisture content, which leads to different creep evolutions even under the same loading level. To account for this phenomenon, another internal variable is introduced to depict the creep behavior of the wood cell wall, which is correlated with the irreversible energy dissipation processes such as stick-slip mechanism in the wood cell wall. Based on five elastic coefficients of transverse isotropy predicted by the present model, the creep behaviors of the wood cell wall with different microfibril angles are theoretically analyzed and show good agreements with experiment results.

• 出版日期2016-11
• 单位同济大学