Dispersion curves for a natural fibre composite panel: Experimental and numerical investigation

The design of orthotropic panels, in which some mechanical properties are associated to high degrees of uncertainty, such as for the natural fibres, is very arduous and often techniques that give local information are needed. In this paper a unidirectional flax–polyethylene panel is experimentally and numerically investigated. Experimentally, for a given distance source–receiver, the group velocities are obtained by processing the guided waves time-transient signals via a time-frequency transform leading to an estimation of the dispersion curves for different fibre directions and frequencies. Test results are then compared and used to validate numerical ones, obtained by means of both Finite Element and Wave Finite Element models.