Some aspects of woof finger joints modeling using FEM and considering wood as material with orthotropic properties

摘要

This study presents the author's research with a view of modeling of stresses in solid wood finger joints using FEM, with application for three species of wood: spruce fir (Picea excelsa), beech (Fagus sylvatica) and oak (Quercus robur). The mechanical properties of wood were taken over the specialized literature. The author started his own research extremely precise, in order to determine the mechanical properties of adhesive in thin stratum (having widths of 0.05...0.2 mm). The special experimental stand conceived by author permits the measuring of linear deformation with a precision of 0.01 mm and of angular deformation with a precision of 0.25 grad for a stress variation of 0.4... 100 N. For the studies of stresses, the orthotropic properties of wood were taken into account, and the effect of the rotation of the main orthotropic directions of wood on the distribution in joints were pointed out. Comparing the theoretical results obtained by modeling of normalized stress in a wood finger joint with the values obtained by experimental research performed on the basis of experimental design method validated the results of this study. The stress modeling constitutes the fundamental element for a subsequent operation for optimum determination of the geometrical parameters for wood finger joints.