Nondestructive Evaluation of Young's Moduli of Full-Size wood Laminated Composite Poles
An exploratory study was conducted to evaluate the Young's moduli of wood laminated composite poles (LCP) by using a free transverse vibration method. Full-size LCP, 6.1 m long and 10.2 cm in diameter, were lab-fabricated with 9 and/or 12 southern yellow pine [SYP] strips of thickness, 1.9 cm, 2.9 cm and 3.8 cm. The frequency of free transverse vibration in a LCP was measured via strain gages mounted on the pole surface through a StrainSmart system. Dynamic Young's moduli evaluated by the free transverse vibration method were compared to these calculated from the measured strains and both agreed very well. The free transverse vibration method can be alternative to the static bending method which is commonly used in the evaluation of bending performance of solid wood beams and wood composite poles. Theeffect of strip-thickness on the Young's Moluli of LCP was observed. However, a significant effect of strip-number on the Young's Moduli of LCP fabricated with 2.0-cm and 3.8-cm strips was not observed.