Shear Modulus and Shear Strength Evaluation of Solid Wood by a Modified ISO 15310 Square-Plate Twist Method

Square-plate twist (SPT) tests were conducted to measure the shear modulus and shear strength using the method, which was a modification of the International Organization for Standardization (ISO 15310) standardized method. In the SPT test, the length/thickness ratio varied. In addition, asymmetric four-point bending (AFPB) tests were conducted, and the shear modulus and shear strength obtained were compared with those obtained by the SPT tests. The shear modulus was obtained effectively by the SPT test when the specimen was thin enough. Although the shear strength was evaluated as higher than that obtained by the AFPB tests, it might be regarded as an apparent value of shear strength when the range of length/thickness is limited. To obtain the actual shear strength by the SPT test, some modification of the equation is required.