COMPARISON OF NONDESTRUCTIVE TESTING METHODS FOR EVALUATING NO. 2 SOUTHERN PINE LUMBER: PART A, MODULUS OF ELASTICITY

摘要

Modulus of elasticity (MOE, or E) is one of the main quality indicators in structural lumber stress grading systems. Due to a relatively high amount of variability in contemporary sawn lumber, it is important that nondestructive evaluation technology be utilized to better discern high-E-value pieces from low-E-value pieces. The research described in this study is from a laboratory test of three nondestructive technologies applied to 343 pieces of visually graded No. 2 southern pine lumber collected across the southeast region of the United States. The evaluated technologies included continuous lumber test in continuous proof bending (Metriguard Model 7200 High Capacity Lumber Tester), transverse vibration (Metriguard E-Computer), and two stress wave tools (Falcon A-Grader and Carter Holt Harvey Director HM200). For each of the nondestructive techniques, results were compared with static E as determined by the four-point static bending tests following ASTM D198-14. In all cases, the nondestructive techniques successfully predicted E for all lumber sizes, with linear regression r(2) values ranging from 0.77 to 0.86.