2014 Volume 63 Issue 4 Pages 320-325
The feasibility of porosity calculate by using X-ray computed tomography (X-ray CT) to evaluate the relationship between the cavities in wood attacked by drywood termite of Incisitermes minor and residual bending strength was investigated. Fifty three wood specimens of Japanese cedar Sugi (Cryptomeria japonica) with 1200mm-length attacked by I. minor were prepared for the measurements of density, dynamic longitudinal elastic modulus, ultrasonic velocity, porosity by using X-ray CT, and bending strength. It was related to high positive correlation between density or dynamic longitudinal elastic modulus, and bending strength. It was seemed that the higher negative correlation between the porosity of center part of 360mm of specimen and bending strength, than the porosity of specimen with 1200mm-length. It was possible to select the specimens more than the standard strength of Sugi with the highest accuracy in the relationship between the dynamic longitudinal elastic modulus and the bending strength, by using the ratio of section modulus calculated from the maximum porosity in center parts divided into six in the longitudinal direction as sifting all the cavities in the radial direction.