This paper experimentally investigates the mechanical properties of rotary veneers peeled from small-diameter hardwood plantation logs, recovered from early to mid-rotation subtropical hardwood plantations. The study aims at providing essential probabilistic data needed to ultimately predict the capacity and reliability of veneered based composites structural products (such as LVL and plywood) from characteristics which can be measured in line during manufacturing. Two species planted for solid timber end-products (Gympie messmate-Eucalyptus cloeziana and spotted gum-Corymbia citriodora) and one species traditionally grown for pulpwood (southern blue gum-Eucalyptus globulus) were studied. The compressive and tensile Modulus of Rupture (MOR) of the veneers, parallel to the grain and for veneer based composite applications, were experimentally investigated. Results show that the compressive MOR for all species typically ranges from 30-50 MPa (for MOE < 12,000 MPa) to 60-90 MPa (for MOE > 22,000 MPa). The tensile MOR is typically lower than or in the range of the compressive MOR for MOE less than 12,000 MPa, while for larger MOE (MOE > 22,000 MPa), tensile MOR greater than 140 MPa were observed. The total knot area ratio (tKAR) of the veneers is also analysed and Weibull distributions were found to provide a good characterisation of the statistical repartition of the tKAR value along the length of a veneer sheet. For each species, equations to best predict a veneer MOR from its measured MOE and tKAR value are derived and fit the experimental results with a coefficient of determination between 0.63 and 0.74. The variability of the MOR of each species was accurately modelled by Weibull distributions, with the distribution parameters determined based on the experimental data. Results shown that southern blue gum and Gympie messmate is the most and least sensitive species to size effects.
This paper quantifies the mechanical properties perpendicular to the grain and in shear of glued rotary peeled veneers, as would be encountered in veneer-based structural products (i.e. by including both the effects of hot pressing the veneers and the glue used during the manufacturing process), of three species recovered from juvenile (early to mid-rotation) subtropical hardwood plantation logs. This underutilised resource has currently little to no commercial value in Australia but proven potential to produce attractive veneer-based structural products. Determining these unknown properties is important as they constitute essential input data to ultimately predict the behaviour and design properties of veneer-based structural products in cost-effective numerical simulations. Two species planted for solid timber end-products (Gympie messmate-Eucalyptus cloeziana and spotted gum-Corymbia citriodora) and one species traditionally grown for pulpwood (southern blue gum-Eucalyptus globulus) are considered in the paper. The dynamic Modulus of Elasticity, compressive and tensile strengths perpendicular to the grain of veneer-based elements, each manufactured from single veneer sheets, were experimentally measured and are analysed herein. These properties are found to have no to weak correlation to the parent veneer sheet dynamic Modulus of Elasticity parallel to the grain, a value which is commonly measured in line to grade veneers. The Shear Modulus (in the longitudinal-tangential plane), also referred to as "Modulus of Rigidity", through-the-thickness and rolling shear strengths were also experimentally measured and the results are discussed in the paper. Little to no correlation to the veneer sheet dynamic Modulus of Elasticity parallel to the grain is also found for these properties. Weibull distributions are fitted to all test results and presented to probabilistically consider the investigated properties in numerical simulations of veneer-based structural products.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.