Shear stress shear strain relation of wood obtained by asymmetric four-point bending test of side-tapered specimen

For determining the shear stress/shear strain relation. we conducted asymmetric four-point bending tests using a side-tapered specimen. Sitka spruce (Picea sitchensis Carr.) was used for the testing material. Rectangular beams with various depths were prepared and symmetric tapers were cut on both side surfaces of the beam so that the failure by shearing preceded that by bending. Asymmetric four-point bending tests were performed under a constant span length condition. and the shear stress/shear strain relations were obtained. In addition to the asymmetric bending tests, Iosipescu shear tests were conducted and the results were compared. The shear stress/shear strain relation could be obtained by the asymmetric four-point bending tests more easily and effectively than by the Iosipescu shear tests when the specimen had a proper configuration. Hence, we concluded that the asymmetric four-point bending test of a side-tapered specimen is promising for determining the shear stress/shear strain relation of wood