Investigation of surface-scratch damage in wood-based materials using scratch testing and X-ray computed microtomography

Previous research demonstrated that combining scratch testing with image-based techniques is a powerful approach for investigating scratch-induced damage mechanisms in untreated and PEG-impregnated wood. However, this methodology has not yet been applied to wood components of modular houses susceptible to surface scratches during handling and transportation under varying relative humidity (RH), where it could support surface quality inspection and end-user satisfaction. In the present study, sawn timber, laminated veneer lumber (LVL), and cladding-board components used in modular houses were subjected to scratch testing and analysed by X-ray computed microtomography (XµCT) to assess scratch resistance, with a focus on the effects of wood’s structural features and RH. The results showed that the wood structure strongly influenced scratching performance, and the components differed in scratch resistance and crack generation. Sawn timber and cladding-board components had higher recovery after scratching and higher scratch resistance based on scratch groove depth, with residual depths ranging from 73 µm to 300 µm. LVL exhibited lower recovery and less crack formation after scratching under varying RH, consistent with the greater dimensional stability provided by its laminated structure. The findings demonstrate the suitability of the proposed approach for scratch assessment in wood-based materials under changing environmental exposure.