Abstract
The applicability of the flexural vibration test to determine the elastic constants of glued laminated timber (GLT) composed of five wood species (ash, Fraxinus spaethiana Lingelsh.; balsa, Ochroma pyramidale Urban.; Japanese cedar, Cryptomeria japonica D. Don; Japanese red pine, Pinus densiflora Sieb. et Zucc.; Sitka spruce, Picea sitchensis Carr.) has been investigated. GLT models were prepared from four laminae with dimensions of 30 (R)×5 (T)×300 (L) mm3. The suitability of Japanese cedar for inner layers in GLTs was tested by flexural vibration test to determine the elastic constants of the laminae and the glued laminated timber. The Young’s and shear moduli were calculated by the Goens-Hearmon regression method based on the Timoshenko theory of bending (TGH method), and the results were compared with the estimated values based on the Young’s and shear moduli measured individually of each lamina. The simple lamination theory was found to be applicable for Young’s modulus but not to shear modulus. The result obtained based on the lamination theory from the shear strain energy was similar to that obtained by the TGH method.
