THE INFLUENCE OF MICROFIBRIL ANGLE ON CREEP SCOTCH PINE WOOD UNDER TENSILE STRESS ALONGTHE GRAINS

摘要

The influence of microfibril angle on the process of creep of microtome wood (Pinus sylvestris L.) samples of constant but varying in different samples moisture content, under different tensile stress levels was studied. The wood density was proved not to be a reliable indicator of its technological quality. Mechanical parameters of wood subjected to tensile stress along the grains were shown to be determined by the microfibril angle in S2 layer of the secondary cell wall. Increase in MFA from 10 to18° was found to cause a linear increase in total creep irrespectively of tensile stress applied and moisture content. For higher MFA the total deformation of wood is greater than that following from linear approximation of the relation for MFA in the range 10-18°. The intensity of specific wood creep increases under tensile stress along the grains and of high moisture content with increasing MFA. For the wood samples of constant low moisture content such a correlation is not always found.