No abstract

Fibre-managed E. nitens has the potential to be used as a feedstock for engineered wood products. This resource, however, has a number of strength-reducing features that need to be removed, and the board needs to be re-joint to be useful in greater lengths for timber construction. A common jointing practice is finger jointing. The suitability of the finger jointing technique for this species is crucial to the mechanical properties of the final product. This study was conducted to explore the influence of finger jointing on the stiffness of sawn boards. A strict manufacturing process of docking and re-joining timber boards in the same location without removing strength-reducing features was conducted to compare the stiffness parameters before and after finger jointing with bending tests. A statistical analysis was conducted. The results showed that the frequency of finger joints along the board did not significantly impact the edgewise stiffness; however, the average flatwise stiffness of the samples with more finger joints was improved slightly. A 10% increase in the end pressure reduced the tip gap significantly but did not influence the stiffness. The finger joint efficiency was 0.824 for the edgewise stiffness of the samples and 1.034 for flatwise stiffness of the jointed sections.

The performance characteristics of finger-joints as a jointing technique for Eucalyptus nitens is crucial for their use in engineered wood products. This research evaluated the strength of the finger-jointed laminations made from fiber-managed E. nitens. A total of 237 specimens with (117 pieces) and without (120 pieces) finger-joints were sectioned from finger-jointed laminations and tested by bending, tensile, shear, and bearing tests. Bending and tensile tests were paired to identify any correlations. The mean value with finger-joints for bending and tensile were 92.1 MPa and 79.6 MPa, respectively. The presence of finger-joints reduced the strength values. Joint efficiencies in bending and tensile are 0.73 and 0.62, respectively. The distributions of bending and tensile strength were similar for the samples without finger-joints. For the samples with finger-joints, tensile strength was significantly lower than paired bending strength. Shear test results show that the short-span test is inefficient in obtaining the shear strength of fiber-managed E. nitens boards. Meanwhile, the finger-joint efficiency in the bearing is 0.86. The prediction models of lamination’s bending, tensile, and bearing strength were established by non-destructive properties as predictors. Bending strength was highly correlated to the modulus of elasticity value, while tensile and bearing strength were correlated to density. This study obtained promising results on finger-jointed boards from fiber-managed E. nitens suggesting they could be suitable for structural purposes.