An approach to viscoelastic behaviour analysis of wood-based panels by an inverse method of characterisation

摘要

The main objective of this paper is to propose an alternative method for viscoelastic characterisation of wood-based panels. Our approach, based on inverse identification methods, allows simultaneous estimation of the whole bending/torsion stiffness matrix of orthotropic plates. Elastic or viscoelastic characterisations are carried out according to the same protocol. The first step consists of optimisation of the experimental set-up, i.e., determination of the best localisation and intensity of the applied stresses and of the best position for boundary conditions. This step is realised for each type of panel using generic algorithms to obtain sensitivities satisfying the test for each stiffness matrix component. An identification procedure is then performed using a finite element program. The measurement of the whole displacement field (500 x 500 mm~2) is made using an optical system. Validation of the elastic identification is carried out by comparison with the mechanical properties obtained from a vibrating test and a simulation tool. Non-conventional analysis of the viscoelastic behaviour of wood-based panels is illustrated for two particular plywood panels.