Nondestructive Evaluation of Green Dimension Lumber Using Stress Wave and Transverse Vibration Techniques

Abstract

Predicting the material properties of wood through nondestructive evaluation (NDE) techniques is a matter of considerable importance for the timber industry. NDE techniques can significantly increase the accuracy of grading of wood compared to visual grading methods. Longitudinal stress wave and transverse vibration nondestructive evaluation techniques have proven to be accurate means of evaluating the quality of wood-based products. Researchers have found strong relationships between stress wave and transverse vibration parameters (e.g., wave velocity and predicted modulus of elasticity) with the actual static bending properties (e.g., modulus of elasticity and modulus of rupture) of dry as well as green wood-based materials [1–3]. Therefore, these NDE techniques can be used to presort or grade structural wood prior to drying. Discarding wood with inferior properties prior to drying can result in significant cost savings in the drying process.