木材の曲げ試験におげる複数の弾性定数の測定

In this study, static bending tests were made with the specimens on which strain gages were bonded, and the plural elastic constants; Young's modulus, shear modulus, and Poisson's ratio, were obtained.
Material used for the experiment was yellow popular (Liriodendron tulipfera L.). Triaxial strain gages were bonded at the centers of the longitudinal-radial (LR) planes of the specimen, and three-point static bending tests were made. The Young's modulus and the Poisson's ratio were obtained by loading on the LR-plane, whereas the shear modulus was obtained by loading on the longitudinal-tangential (LT) plane. These bending tests were made under the various span/depth ratios, and the influence of the span/depth ratio on the elastic constants was examined. On the other hand, the Young's modulus and the Poisson's ratio were measured by the uniaxial tension and compression tests, and the shear modulus was obtained by the torsion test independently. The obtained elastic constants were compared with each other, and the validity of the measurement method was examined.
The elastic constants obtained from the bending tests showed rather good agreement with those obtained from the other conventional methods. Therefore, it was concluded the elastic constants can be obtained effectively by the static bending used here.