Lumber Rolling Characteristics Introduced on the Basis of Uniaxial Compressive Stress-Strain Curve

—Studies on the Rolling of Wood III—

Abstract

Uniaxial transverse compression tests on SUGI lumber (Japanese Ceder) are performed in a furnace that can maintain temperature and humidity uniformly, and the effects of parameters such as temperature, moisture content and strain rate on the stress-strain curve, which includes the unloading stage, are examined. As the factors used to evaluate lumber rolling characteristics, yield compressive stress, maximum compressive stress and recovery ratio in the unloading stage are selected from the compressive stress-strain curve. We investigate how these factors are affected by the above-mentioned parameters. For example, recovery ratio decreases in the case of lower moisture content and lower temperature. Approximate formulas of rolling load and torque containing the above-mentioned factors are introduced and the effects of the parameters on the rolling load and torque are discussed.