Effect of Growth Rings Per Inch and Specific Gravity on Compression Perpendicular to Grain in No. 2: 2 by 8 and 2 by 10 Southern Pine Lumber

Abstract

AbstractSouthern pine lumber 2 by 8s and 2 by 10s from across the Southeast were used as the parent material source for this study. Fundamental data were collected for each piece of lumber: growth rings per inch (RPI), presence of pith, and specific gravity (SG), among other information. After mechanical property evaluation through static bending, small clear specimens were cut from the lumber pieces and tested for compression perpendicular to grain (C⊥). Those values were then compared with 2 by 8 and 2 by 10 average RPI and density. The results were significant for both tests. Therefore, a segmentation of the growth ring data into groups of <3, 3 to 5, and >5 RPI was conducted. Correlations were run specific to each group, per both lumber sizes, and still significance was found. Segmentation of SG was not significant only for 2 by 8 SG <0.4. The results suggest that SG is a better predictor of C⊥ than RPI alone due to statistical significance found during these analyses.