木材の弾性定数および降伏応力の決定法

In this paper, we formulated the stress-strain and stress-plastic strain relationships, and examined the determination method of the Young's modulus and the yield stress which dominate the stress-strain property.
Agathis (Agathis sp.) and katsura (Cercidiphyllum japonicum Sieb. and Zucc.) with various grain orientations were used for the specimens. These specimens were uniaxially compressed, and the stress-strain relationship was formulated by Ramberg-Osgood's power function. Then, the strain component was separated into the elastic and the plastic parts, and the stress-plastic strain relationship was formulated by Ludwik's power function. The yield stress was obtained by extrapolating the plastic strain to zero. The obtained Young's moduli and the yield stresses were compared with those determined visually, and the validity of our proposal was examined.
From the experimental results, we concluded that the Young's modulus and the yield stress were determined properly by the formulation process proposed here.