Characterizing Variability of Commercial Oriented Strandboard: Bending Properties

Abstract

To characterize the variation in bending modulus of elasticity (MOE) and modulus of rupture (MOR), two commercial oriented strandboard (OSB) products were selected. Master panels from multiopening, large hot presses were cut into standard panels of 1,220 by 2,440 mm, and then a total of 3,420 bending specimens were prepared in a continuous order and tested. The variations in bending properties were compared in terms of coefficient of variation (CV) and property differences both between and within master panels. The differences were evaluated by conducting analysis of variance and least significant difference tests. The correlation between MOE and MOR was also investigated. The results showed that the thicker OSB had less variation in bending properties than the thinner product. The variation of MOE (CV = 12% to 16%) was lower than that of MOR (CV = 20% to 22%). Although no significant differences were found in bending MOE and MOR between master panels, significant variations were noted in MOE and MOR within master panels. The differences in MOE and MOR between standard panels varied from 4 to 11 percent, and those along and across the forming line could vary from 8 to 17 percent and from 33 to 59 percent, respectively. The results suggest that product uniformity needs to be improved both along and across the forming line to lower production cost and improve product performance. The relationship between MOE and MOR was linear, with R 2 around 0.7.