EXPERIMENTAL INVESTIGATION OF MIXED-MODE CRACK GROWTH PROCESS IN WOOD MATERIAL

Rostand Moutou PITTI
Conf.dr. - Universitatea Polytech'Clermont Ferrand
Address : Campus des Cezeaux, 24, Avenue des Landais, BP 206, 63174 Aubiere Cedex France
Tel. (+33) (0)4 73 40 75 00
E-mail: rostand.moutou.pitti@polytech.univ-bpclermont.fr

Frederic DUBOIS
Prof.dr. - Universitatea Limoges - GEMH Laboratory,
Address: Bd. Jacques DERCHE, 19300 Egletons, France
Tel. +33(0)5 55 93 45 41. E-mail : frederic.dubois@unilim.fr

Octavian POP
Conf.dr. - Universitatea Limoges - GEMH Laboratory
Address: Bd. Jacques DERCHE, 19300 Egletons, France
Tel. +33(0)5 55 93 45 41. E-mail : ion-octavian.pop@unilim.fr

Abstract: Due to the complex wood anatomy and the loading orientation, the timber elements are subjected to a mixed-mode fracture. In these conditions, the crack tip advance is characterized by mixed-mode kinematics. In order to characterize the fracture process function versus the loading orientation, a new mixed-mode crack growth timber specimen is proposed. In the present paper, the design process and the experimental validation of this specimen is proposed. Using experimental results, the energy release rate is calculated. The calcul consists on the separation of each fracture mode. The design of the specimen is based on the analytical approach and numerical simulation by finite element method. The specimen particularity is the stability of the crack propagation under a force control.

Key words: wood, fracture, energy release rate, mixed mode, marks tracking.

REFERENCES
CHEN, F.H.K., SHIELD, R.T. (1977). Conservation Laws in Elasticity of the J-integral Type. In: Journal of Applied Mechanics and Physics, 28 (1): 1-22.
DESTUYNDER, P., DJAOUA, M., LESCURE, S. (1983). Quelques remarques sur la mecanique de la rupture elastique. In : Journal de Mecanique Theorique et Appliquee, 2, (1): 113-135.
DUBOIS, F., CHAZAL, C., PETIT, C. (2001). Viscoelastic Crack Growth Process In Wood Timber: An Approach By The Finite Element Method For Mode I Fracture. In: International Journal of Fracture. 113 (4): 367-388.
GUITARD, D. (1987). Mecanique du materiau bois et composites. Cepadues - Editions.
MOUTOU PITTI, R., DUBOIS, F., PETIT, C., SAUYAT, N. (2007). Mixed Mode Fracture Separation In Viscoelastic Orthotropic Media: Numerical And Analytical Approach by the MOn - integral. In: International Journal of Fracture, 125 (3): 181-193.
RICHARD, HA. (1981). A NEW COMPACT SHEAR SPECIMEN. In: International Journal of Fracture. 17 (5): 105-107.