Tribological mechanisms involved in friction wood welding

Friction wood welding (FWW) is an innovative process allowing wooden parts to be joined without any external material addition. Surprisingly, whereas extensive investigations on chemical reactions involved in FWW were carried out, no tribological studies have ever been performed to characterize the underlying frictional mechanisms. This paper addresses this limitation through linear reciprocated friction tests performed on beech wood samples under various contact pressures and moisture contents. Tests results coupled with a characterization of surface modifications highlight the variety of frictional mechanisms. Ultimately, this study also suggests that the friction coefficient is a relevant tool in order to control the process in the goal of optimizing the mechanical strength of the welded assembly.