Micromechanics of Wood Cell Wall
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Micromechanics of Wood Cell Wall Lik-ho Tam and Denvid Lau MRS Advances / FirstView Article / July 2016, pp 1 - 9 DOI: 10.1557/adv.2016.50, Published online: 26 January 2016
Link to this article: http://journals.cambridge.org/abstract_S2059852116000505 How to cite this article: Lik-ho Tam and Denvid Lau Micromechanics of Wood Cell Wall. MRS Advances, Available on CJO 2016 doi:10.1557/ adv.2016.50 Request Permissions : Click here
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MRS Advances © 2016 Materials Research Society DOI: 10.1557/adv.2016.50
Micromechanics of Wood Cell Wall Lik-ho Tam1 and Denvid Lau2 1 Ph.D. Student, Department of Architecture and Civil Engineering, City University of Hong Kong, Hong Kong, China 2 Assistant Professor, Department of Architecture and Civil Engineering, City University of Hong Kong, Hong Kong, China ABSTRACT The damage evolution and structural failure in trees and other plants are mainly originated from the plastic yielding in the wood cell wall at the microstructural level, which consists of cellulose fibrils embedded in a polymer matrix of hemicellulose and either lignin or pectin. Understanding the mechanical behavior of wood cell wall at the plastic regime is critical to the investigation of the fracture characteristics of trees at macro-scale. In this research work, the wood cell wall, which consists of cellulose fibrils, hemicellulose chains and lignin macromolecules, is modeled at the mesoscale to investigate the mechanical responses under deformation. By examining the force-strain relationship, the mechanical behaviors of the wood cell wall at the plastic yielding range are obtained, which are initiated from the slippage between the fibrils and polymer matrix. The simulation results are compared with experimental measurements and theoretical predictions to provide a bottom-up description of micromechanics of the wood cell wall, and to explain the damage evolution and structural failure occurred at the larger scales. The wood cell wall investigated here can be applied to the construction of wood hierarchical structure as a basic unit and adapted to the studies of different natural materials. INTRODUCTION Reports on tree accidents have been increasingly seen in recent years, which have aroused enormous public concern. The wind force under typhoon and strong monsoon wind is one of the principal reasons for the tree failure, causing a loss of the social wealth1. In order to optimize the tree longevity and prevent the catastrophic death, it requires an in-depth understanding of the tree behaviors when subjected to the wind load. Such fundamental knowledge enables one to identify the tree that is at risk of external strikes, and to provide structural supports for the tree before the irreversible decline occurs. As tree features a hierarchical structure, the wind forces on the tree trunk cause mechanical loadin
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