Nondestructive Evaluation of Southern Pine Lumber

Southern pine (SP) lumber is the primary softwood material in the United States. The main procedure during lumber grading process is the identification of the strength reducing characteristics that impacts the modulus of rupture (MOR). Non-destructive evaluation technology can be used to identify higher-stiffness material. This study investigated the use of vibration methods to evaluate the mechanical properties of southern pine lumber. Significant correlations between the properties determined by non-destructive techniques and the static MOE were found. No strong correlations were found for MOR because it is related to the ultimate strength of material, often associated with the existence of localized defects, such as a knot. Non-destructive measurements, visual characteristics, and lumber density were used as independent variables. Linear models were constructed to indirectly estimate the MOE and MOR. The variables selected was dynamic modulus of elasticity (dMOE) to predict MOE. Adding density and knot diameter ratio to the model it was possible to develop a prediction model for MOR. It was possible to improve predictability of strength (MOR) with a combination of non-destructive and knot evaluation