Young's modulus and shear modulus of open-hole spruce measured by vibration tests

Longitudinal and flexural vibration tests were conducted using open-hole Sitka spruce specimens, and the effects of the size and location of the open hole on the measurement of the nominal Young's modulus and nominal shear modulus were investigated. The nominal elastic moduli often decreased as the size of the open hole increased, and the hole was located close to the mid-length of the specimen. However, the decreasing tendencies were characterised according to the direction along which the vibration was excited. To consider these phenomena, an empirical equation for deriving the nominal elastic modulus corresponding to the size and location of the open hole is proposed. The effects of the open hole were appropriately predicted using the proposed equation.