Recherche d’un protocole expérimental non destructif de caractérisation mécanique des grumes

Details

Supervisors

Latteur, Pierre

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil des constructions, à finalité spécialisée

Abstract

enWood is a durable building material and has good mechanical properties in its raw state. Unfortunately, because of the many transformations, it is often expensive compared to concrete and steel. It could then be interesting to use wood in its simplest form: a debarked and delimbed trunk commonly called a log. This thesis focuses on how to mechanically characterize logs in order to offer the possibility of using them in construction. The study is based on tests in bending of thirty logs of three different species measuring from 6 to 8[m] and having a diameter of 35 to 45[cm]. These tests allowed us to determine the essential parameters to characterize them. Test batteries on samples were also carried out to understand the long-term behavior of this material. It was found that seven factors should be defined to determine the expectations of a log in a project. The results were compared with those commonly accepted in the standards and those obtained by V. HOUBEN (2022). Many similarities are observed. The tests on specimens showed that the coefficients proposed by the Eurocode were certainly safe, but adaptable to each species. Finally, we propose a first industrial protocol adapted to the needs of the wood industry. This protocol can be automated and implemented in a sawmill. It includes a pre-grading, a drying, a machining and a mechanical test. The latter is composed of several loading cycles to check if the log can support an ultimate load without being damaged. Early signs of weakness were determined in order to anticipate any degradation and to interrupt the test in order to preserve the mechanical properties to allow another valorization.