In situ damping identification of plant fiber composites using dynamic grid nanoindentation

Damping properties of plant fiber composites have been quite widely investigated based on macroscale techniques. Considering their heterogeneous and hierarchical microstructure, it is also necessary to study their damping behavior at the microscale to provide better insight into the dissipation origins and mechanisms. This article proposes a characterization of the dynamic mechanical properties of flax/GreenPoxy composites at microscale using dynamic grid nanoindentation technique. Two loading protocols are used: the classical Continuous Stiffness Measurement method (CSM) and a new method called Constant Amplitude Measurement method (CAM). Results show experimental protocols (CAM or CSM) do not have significant effect on storage modulus while they significantly affect the loss factor. The grid nanoindentation technique also provides an interesting map of the viscoelastic properties at the microscale in the cross-section of the composites and the damping contribution of the various components are highlighted.