Volume 33, Issue 4 (July 2005)
Effect of Additional Mass on the Young's Modulus of a Wooden Beam
We investigated the influence of an additional mass bonded on a wooden beam on its Young's modulus based on Euler-Bernoulli's elementary theory of bending. Thin rectangular beams of Sitka spruce (Picea sitchensis Carr.) were used as the experimental materials. After bonding an iron piece on a beam, a free-free flexural vibration test was performed to obtain Young's modulus. The Young's modulus decreased with an increase in the resonance mode number without iron pieces, but there was no such tendency when the iron piece was bonded on the specimen. This was because the constants that are needed for the Euler-Bernoulli theory are changed by the additional mass. We developed an equation that contains the effects of the weight and position of the iron piece on the constants. The Young's moduli calculated by this equation were very similar to experimental values without an iron piece.