Effect of moisture and temperature upon the compression strength parallel to grains of wood

This articles presents the results in the research into the effect of moisture and temperature upon the compression strength parallel to grains (σ,,) of wood for beach, oak, poplar, fir and spruce. The investigation have been conducted for moisture range between 4 . . . 24 % and temperature range between 20° and 80° (90°) C. Estimated results show that the compression strength depends of moisture in the hygroscopic area, more exactly its decrease with increasing of moisture can be described by equotation in form.

σ,, = 10^((a+bu+cu)^2)

With increasing of temperature during constant moisture of wood, compression strength decreases and for that it have been estimated the equotation in form

σ,, = 10 + bt

During simultaneous influence, moisture of wood shows the higher effect to decreasing of compression strength parallel to grains of wood. Effect of temperature is more expressive for species with higher density and that effect decrease with decreasing the density of wood.