| ABSTRACT: | MECHANICAL PERFORMANCE OF WOOD CONSTRUCTION MATERIALS
M. P. Luong
Ecole Polytechnique; Palaiseau; France
Damage and failure behaviour of wood in tensile, compressive or shear loading are an important
consideration in connection with design or regulations of wooden structures. Failure may occur at stresses
below its static strength.
The aim of this paper is to illustrate the use of infrared thermography as a nondestructive and non contact
technique to detect, to observe the physical process of failure and to depict the onset of damage, crack
propagation and/or flaw coalescence due to the thermomechanical coupling when the wood specimen is
loaded until failure.
When a wood or a structural wood product is loaded, it deforms as a whole in spite of its heterogeneous
characteristics and its localised defects. Stress concentrations occur and result in localised forces that are
sufficient to promote plasticity and inelasticity or both. At the structural level, breakdown appears as micro
cracking and possibly slippage at component interfaces producing heat dissipation. Failure mechanisms of
wood specimens in different directions of anisotropy are readily evidenced by infrared thermography.
The thermomechanical coupling of wood materials under loads demonstrates the relevant use of infrared
thermography as a nondestructive, real-time and non contact technique: (i) to observe the progressive
damage process and failure mechanism of wood materials, (ii) to detect the occurrence of intrinsic
dissipation localisation and to evaluate the limit of a progressive damaging process under load beyond
which the material is destroyed.
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