EXPERIMENTAL METHOD FOR DETERMINING FRACTURE
PARAMETERS OF GLUED WOOD:
CASE OF MDF

Abdellatif ZERIZER
Prof.Dr. - Université M'hamed Bouguerra - Faculté des Sciences de l'Ingénieur
Address: 35000 Boumerdes, Algeria
Tel / Fax: (024) 81 64 08. E-mail: zerizer_ab@yahoo.fr

Patrick MARTIN
Prof.Dr. - Ecole Nationale Supérieure d'Arts et Métiers
Address: 4 rue Augustin Fresnel, Metz, France
Tel: 03-87-37-54-30 57078. Email : patrick.martin@metz.ensam.fr

Pascal TRIBOULOT
Prof.Dr. - Ecole Nationale des Sciences et Industries du Bois (ENSTIB)
Address: Allée des hêtres 88000 Epinal, France
Email: triboulot@enstib.uhp-nancy

Abstract:
The aim of this paper is to study an experimental method for determining the fracturing process of MDF (Medium Density Fiberboard) composite wood panels. Even if MDF is considered an isotroic material, the heterogeneity of density through its thickness confers MDF a much better machining quality of the edges nearby the panel faces than inside. For many finished products, the edges must be machined to give a suitable form before any surface coating. Compared to preset cutting conditions, the rate of fracture energy G1c is measured by means of a test usually used in fracture mechanics "DCB" (Doubls Cantilever Beam). The analysis of the results makes it possible to qualify the resistance of the samples of MDF glued two by two. The thickness effect of the chip Em (obtained my milling the MDF samples) is clearly illustrated in our experiments. Moreover, it is possible to find a linear relation between G1c and the criterion of roughness Ra, the thickness of the chips being limited by the industrial conditions. We conclude that the chip thickness interval of 0,20 to 0,35mm is the most significant parameter for a high performance of gluing.

Key word: fracture process, "Double Cantilever Beam" test, MDF, various cutting conditions.