Ganne-Chédeville, Christelle (2008). Wood welding by linear friction: investigations and understanding of the physical and chemical modifications and development of an innovative technology. (Dissertation, Université Henri Poincaré - Nancy I)
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Wood welding by linear friction allows bonding of timber in a few seconds without unsing any adhesive. The adhesion is essentially due to the wood fibres entanglements which are embedded in a melted and recured intercellular polymers matrix. But the bonding interphase formation mecanism and the machine parameters and wood substrate influences are not clearly understood. Consenquetly, the goal of this study was to analyse the different factors which are influencing the joint characteristics in order to understand the physical and mecanical process mecanism. Infrared temperature measurements brought several informations on the process. On the other hand the welded joints were caracterized by microscopy, mechanical testing, fracture mechanics, interphase and smokes chemical analysis. The results were used to developp and to verify a physical and chemical scenario describing, in successiv steps, the interphase microstructure formation. A first numerical thermal model for Fagus sylvatica was build allowing the thermal simulation of the process. The aim of the last part of the study is the understanding of the wood substrate influences on the process. The variablity problematics like those due to wood species, wood anatomy or surface quality were investigated. Modified wood and wood panels were successfully welded. The research results were applied in the frame of a preindustrial development. This has reveal new scientific and technical problematics but also a great optimization capacity of this technology.