DENSIFIED WOODEN NAIL FOR ADHESIVE- AND METAL-FREE TIMBER ASSEMBLES
Authors/Creators
- 1. InnoRenew CoE; University of Primorska
- 2. IPM ENGINEERING s.r.o.
- 3. Oregon State University
- 4. Luleå University of Technology
Description
The widespread utilisation of adhesives to assemble engineered wood products may lead to environment
and recycle concerns. To improve materials sustainability and recovery at the end-of-life, it is preferable to replace
adhesive with mechanical lock-in fasteners such as wood-based connectors. Nowadays, the development of robotic
fabrication technologies and wood modification technologies brings the opportunity to rejuvenate traditional woodjoining
methods. In this study, thermo-hydro-mechanical densified wooden nail were proposed as an adhesive- and metalfree
connector for timber assembles. The densification ratio varied between 40 to 68%. Research has been performed in
order to determine the effect of densification on the compression behaviour of wood in the form of nails. The result
showed that densification with high compression ratio can successfully increase the density and modulus of rupture of
wood, while its influence on modulus of elasticity is not obvious. A set of prototype nails made of densified wood was
manufactured. In addition, preliminary insertion tests into wood samples were carried out and served for insertion process
understanding. The results obtained reveal a potential for using the densified wooden nail connectors for substitution of
adhesive or metal connectors. However, the “success ratio” for proper inserting of wooden nails was not satisfactory. It
was observed that the excessive dynamical loading induced buckling failure of the nail during hand-operated insertion.