A parametric study of material damping in fibre-reinforced plastics

In this paper, the important parameters causing energy dissipation in unidirectional glass fibre-reinforced epoxy laminae are investigated. Three parameters are considered: matrix and fibre damping and the effect of the interface. An energy balance approach is used to find closed-form relationships between material properties and design parameters. This approach shows that the fibre or matrix contribution to damping lies in the partition of elastic strain energy, which is highly dependent on the elastic properties of the fibres and matrix. A three-phase model is developed which clearly shows that a poor quality interface, with low elastic stiffnesses, has a significant effect on the energy damping capacity of the unidirectional laminate. However, in the case of a normal quality interface, more sensitive and accurate damping measurement methods are needed to identify the contribution of interface damping to the global laminate damping behaviour.