Improving strength grading of lumber by grain angle measurement and mechanical modeling
Article dans une revue avec comité de lecture
Timber strength grading has become a major issue in the European Union during the last years, due to the introduction of the Eurocode 5 and all its related standards. Currently, the most performing strength grading machines are able to locally detect the boards’ knots sizes and positions and interpret this information through adapted grading models. The best lead to improve their accuracy seems to be the introduction of new information about the boards and adapt the mechanical model to take them in account. Small grain angle causes high reduction of clear wood’s mechanical properties, local value of slope of grain appears to be of high interest. The aim of this study is to quantify the additionalaccuracy that grain angle information can bring toan optical scanner used as a strength grading machine. A specific grading model has been developed accordingly, and the results obtained for different machine / model / loading combinations are presented. These results show that slope of grain measurement can significantly improve the accuracy of the optical scanner, for both MOE and MOR estimations.
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Modelling mechanical properties of spruce and Douglas fir timber by means of X-ray and grain angle measurements for strength grading purpose Article dans une revue avec comité de lectureVIGUIER, Joffrey; BOURREAU, Damien; BOCQUET, Jean-François; POT, Guillaume; BLERON, Laurent; LANVIN, Jean-Denis (Springer Verlag, 2017)This study proposes a model using data from a scanner (X-ray and grain angle measurements) to perform strength grading. The research also includes global measurements of modulus of elasticity (obtained by vibrations and ...
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