FRACTURE OF WOOD UNDER THERMO-VISCO-HYDRO-MECHANICAL LOADINGS

Rostand Moutou Pitti (1) , S E Hamdi , Frédéric Dubois (2)

1 IP - Institut Pascal
2 GEMH - Groupe d'Etudes des Matériaux Hétérogènes

The identification crack initiation and crack growth process is very important in mechanical and civil engineering materials as wood in order to avoid the total collapse of structures. In consequence, the utilization of wood (Douglas Fir in this work) in external conditions more or less protected constitute an important outlet. However, in presence of climatic variations, the long terms loads and especially the crack initiations, the mechanical behaviour of these structures is found highly modified disturbing their implementation and shortening their life in service. In this specific case, it appears necessary to study these species submitted to extreme loadings conditions and crack growth process. However, the crack growth rate in wood-based structures is commonly expressed as a function of stress intensity factor K or energy release rate G. It is shown that for a stable crack propagation (G is a decreasing function of crack length), crack growth resistance is not constant, but changes with crack propagation. Temperature (T) and moisture content appears to be responsible for the changes, and leads to the formation of the so-called process zone [1] with time dependent effects. For an unstable crack growth, the effect of the process zone even more dramatic [2]. The aim of this paper is to investigate the effect of T and MC changes on wood fracture properties, focusing on crack driving forces, such as viscoelastic energy release rate during the humidification process

Domaines: Matériaux; Structures; Matériaux composites et construction; Construction durable

Rostand Moutou Pitti, S E Hamdi, Frédéric Dubois. FRACTURE OF WOOD UNDER THERMO-VISCO-HYDRO-MECHANICAL LOADINGS. 14th International Conference on Fracture (ICF 14) , Jun 2017, Rhodes, Greece. ⟨hal-01616969⟩