Abstract:

In this paper, seventeen species of hardwood were chosen in the variation range of 100-1300kg/m³ wood density. The large Transverse compression deformation test and the collection of quantitative data were conducted under six kinds typical conditions of wood compression. (The conditions are the combination of three kinds of conditions which are airdried. 20℃, saturated water. 20℃ and saturated water. 100℃ with the restricting conditions.)On the basis of data analysis, the formulas which express quantitatively the relationship between stress and strain and stain were founded as following: In the formulas above, E is elastic modulus in transverse direction; σ_y is yield stress; ε_y is yield strain; ε_d is a measure of the strain when all of the pore space in wood is squeezed out. C is the armature of increasing speed of stress when strain above the yield point; ρ and ρ_s reefer to density of wood and material density of the cell wall respectively. K is a constant that depend on the factors such as the restricting conditions of compressive test, 0≤K≤1.The formulas above is adaptable to the tree species and the compressive conditions under the test conditions in this paper. Moreover, the results of calculation were very concordant with the data of experiment.

Key words: Large compressive deformation, Transverse direction, Stress-Strain diagram