Free and Forced Vibration Characteristics of a Flax Fibre Reinforced Composite Beam with Viscoelastic Core

Abstract

Abstract In this study, free and forced vibration characteristics of a flax fibre reinforced composite beam with a viscoelastic core have been investigated using theoretical and experimental approaches. The theoretical approach involves finite element method incorporating layerwise modelling considering classical laminate theory for top and bottom composite face sheets. The transverse displacement field is assumed to be same for all the layers, whereas the axial displacement field for the viscoelastic core is linearly interpolated in terms of the displacements of the two face sheets. Natural Frequencies of the beam in cantilever configuration and transient response of the tip of the beam subjected to base harmonic excitation have been determined under the theoretical approach. The experimental approach involves sine sweep testing and base excitation testing for determination of natural frequencies and transient response of the tip respectively and the tests have been done using an electrodynamic shaker. The results obtained from both the approaches agree closely with each other and illustrate the effect of introduction of viscoelastic core in the natural fibre reinforced composite beam.