This project was concluded in 2020.
Carl Tryggers stiftelse för vetenskaplig forskning
1 Jan–31 Dec 2020
Forestry and wood technology (Department of Forestry and Wood Technology, Faculty of Technology)
More about the project
Wood composites (particleboards, medium and high density fibreboards, hardboards, oriented strandboards) are widely used in the furniture and construction industry. Changing requirements in these industries require inclusion of functionally optimized wood composite products.
Understanding composites’ properties is critical to structural and fire engineering strategies in their application areas. Density is a fundamental property for wood composites due to its predominant effects on mechanical, dimensional and thermal properties.
Wood composites have an unbalance density profile along their thickness, so called vertical density profile (VDP), which is mainly formed from the hot-pressing process. Thus, wood composites are highly inhomogeneous materials whose properties are a lot more complicated than other homogenous materials.
Due to the absence of VDP in various projects, it is unlikely for engineers to accurately predict the wood composite behaviour. Predictions using a uniform VDP leads to less reliable outcomes as the effect of density variation within the wood composite is ignored. VDP is a major quality control parameter also in the laboratory for realizing new wood composites by using different furnish materials, adhesives and press parameters, while according to EN 312 standard the maximum density deviation should not exceed ±10%.
A laboratory density profile measuring unit of wood composites is based on the principle of the radiometric penetration and an X-ray tube is used as radiation source. The measuring process is without contact and results are acquired within seconds. Data input required are the geometry of the specimen, mass and humidity. The determined density values are stored in a database, and then the density profile is determined in form of a graphic and a measuring value table for each specimen.
The instrument will complement the existing infrastructure on wood composites at Linnaeus University, Group of Forest Products. This is the only research group at Swedish Universities with a focus on wood composites, while the instrument does not exist in other Universities or research institutes. It will be used directly in ongoing and future projects towards more functional wood products, and it will be useful for commercial wood composite users and engineers.