The use of adhesive technologies in wooden construction offers several advantages over solid-sawn wood, allowing a more efficient exploitation of forest resources. Moreover, it permits engineers to design lighter and more innovative structures that offer better performance. Although there have been great achievements in the science and engineering of wood adhesion, the characterization and modeling of bond strength of the adhesive at the adherend wood-wood interface remains an open issue.
The purpose of this project is to perform a comprehensive numerical and experimental investigation about the identification of cohesive laws for adhesively-bonded wood joints, under pure modes I and II and mixed mode I/II loading. Our ambition is to develop a suitable method for complete identification of the cohesive laws, without any a priori choice of its shape. Two different kinds of identification methods will be examined: (a) inverse methods, requiring both some numerical procedure and experimental data, and (b) direct or totally experimental methods. The key feature of the work to be carried out is the use of different techniques and measurements to assess the cohesive law. Besides the global mechanical response of specimens (loading–displacement curve), we intend to measure the near crack tip strains with digital image correlation technique (at the surface of specimens) and embedded optical fibre Bragg sensors (FBGs). Three fracture tests are envisaged: the double cantilever beam (DCB) to apply the mode I loading, the end notched flexure (ENF) test for mode II loading and the mixed mode bending (MMB) test for mixed mode I/II loading.