Articles
BIOMECHANICS OF TREES AND WOOD FOR HAZARDOUS TREE ASSESSMENT
Article number
496_25
Pages
197 – 208
Language
Abstract
This paper states the general principles of mechanical analysis applied to trees.
The following peculiarities are emphasized: (i) the complicated geometry (compared to usual structures of engineers), (ii) the heterogeneity of wood at different levels, (iii) the influence of radial growth that lead to unusual fields of stresses, (iv) growth stresses and strains due to internal physical and chemical phenomenon during wood formation that lead to pre-stresses superimposed to external loads, (v) methods and commercial devices for the appraisal of internal defects, (vi) the biomechanical adaptations and the resulting deep interactions between tree biology and tree mechanics to allow a reliable diagnosis.
Thus any mechanical analysis is based on an underlying model, appraising the risk from the choice of a safety factor, assuming simplifying hypotheses, that must be discussed and validated experimentally.
Such a quantified and integrated analysis is not explicit yet in the expert practice.
The following peculiarities are emphasized: (i) the complicated geometry (compared to usual structures of engineers), (ii) the heterogeneity of wood at different levels, (iii) the influence of radial growth that lead to unusual fields of stresses, (iv) growth stresses and strains due to internal physical and chemical phenomenon during wood formation that lead to pre-stresses superimposed to external loads, (v) methods and commercial devices for the appraisal of internal defects, (vi) the biomechanical adaptations and the resulting deep interactions between tree biology and tree mechanics to allow a reliable diagnosis.
Thus any mechanical analysis is based on an underlying model, appraising the risk from the choice of a safety factor, assuming simplifying hypotheses, that must be discussed and validated experimentally.
Such a quantified and integrated analysis is not explicit yet in the expert practice.
Publication
Authors
M. Fournier-Djimbi, B. Chanson
Keywords
Growth stresses, mechanical modeling, wood heterogeneities, reaction wood, internal defects
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