Dynamic modulus of elasticity of drilled wooden beams

Abstract

In this study, researchers attempted to investigate the effects of drilling and hole widening on the dynamic response of wood using nondestructive methods. Clear and sound rectangular (2 × 2 × 36 cm R × T × L) bars were prepared from Beech timber (Fagus orientalis) and drilled in four steps with 3, 5, 8 and 10-mm diameters at central points in length on the tangential (LT) surface in the radial (LR) direction. To evaluate the longitudinal modulus of elasticity, the free–free bars before and after drilling procedure were brought to free flexural vibration test. To study the effects of stepwise hole widening, the dynamic evaluations were compared with two flexural vibrations parallel to LR and LT surfaces. The holes decreased the longitudinal modulus of elasticity values when the bars were vibrated in LR, while the values in LT remained significantly constant throughout the stepwise drilling. The differences due to longitudinal modulus of elasticity values comparing LR and LT free flexural vibrations were proposed as defect indicators.

Keywords:

• defect
• drilling
• elasticity
• flexural
• vibration

Acknowledgements

This article reports some of the findings in a research project entitled as ‘A Study on the Possibility of Discovering the Holes Inside Wood Using Vibration NDT’, which was carried out by these researchers in 2009. They would like to express their sincere appreciation and gratitude to Islamic Azad University, Karaj Branch, Iran, without whose constant support this project would have hardly been accomplished.

A special thank you is dedicated to Natasha Qale (PhD in English literature and the CamTESOL international editor) for her kind assistance with the English revisions and Mr Rahi Ghaffarian for creating drawings.

Notes

1. Email: [email protected]

Additional information

Notes on contributors

Loïc Brancheriau

1