3D structural characterisation, deformation measurements and assessment of low-density wood fibreboard under compression. The use of X-ray microtomography.

A low-density wood fibreboard has been compressed along its transversal direction. The experiment was carried out in ESRF synchrotron (ID19) and X-ray microtomographic images were recorded for each state. Stipulating that the fibreboard is a discontinuous material essentially made of air, that the compression simply re-organises the spatial distribution of the fibres and does not involve their intrinsic mechanical properties, we are able to deduce the material points density variations along the thickness of the panel. Good agreement is achieved between the macroscopic deformation of the sample and the microscopic compression rate evaluation. Then, the modifications of structural parameters are investigated by 3D image analysis. The relationship between the local structure and the behaviour of the wood fibreboard are deduced. Finally, a modelling approach allows the local densification to be predicted and confirms the initial hypotheses about the local behaviour of the material. In particular, polyester bonds are not involved.

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