Comparing idealized acoustic wave behavior to that observed in clear wood and lumber

Abstract

In this paper, the behavior of an acoustic wave within an idealized wood specimen are compared and contrasted to the acoustic behavior observed in clear wood and lumber using signal processing and analysis. Published information on the physical and mechanical properties of clear, defect-free wood is used to derive a model of acoustic wave behavior. The model closely matches results observed from defect-free wood. Wave behavior is also examined in a series of wood specimens containing strength reducing defects such as knots and slope of grain. Differences between the idealized model results and those observed from the specimens are noted and attributed to characteristics observed through visual inspection and X-ray scanning. A series of metrics are examined with the goal of developing mathematical indicators from the acoustic signals to assess how the presence of defects affect wood strength. This research paper is the first phase of a study designed to examine the use of advanced signal processing techniques with acoustic based lumber grading technologies to evaluate the modulus of elasticity and strength of structural lumber.

Citation

Franca, Frederico; Senalik, C. Adam; Seale, R. Daniel; Ross, Robert R.; Shmulsky, Rubin. 2019. Comparing idealized acoustic wave behavior to that observed in clear wood and lumber. In: Wang, X.; Sauter, U.H.; Ross, R.J., eds. Proceedings: 21st International Nondestructive Testing and Evaluation of Wood Symposium. General Technical Report FPL-GTR-272. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory: 194-203.