Structural dynamics of individual plant fibres: a contribution to the understanding of damping properties of bio-based composites

The field of bio-based composites faces challenges in understanding the physical mechanisms providing excellent compromise between stiffness and damping. Potential sources of damping, including the matrix, the fibre, and the interfaces (fibres/fibres and fibres/matrix) are identified in the literature. To better understand damping at the composite scale, it is necessary to understand the dissipation causes at each scale of the material. However, the mechanical characteristics of individual plant fibres, such as modulus and damping, can be uncertain due to the complexity of measuring their properties at such small scale (10 µm diameter, a few mm long). To address this knowledge gap, this work proposes a method based on dynamic response of individual plant fibres. By exciting the fibre with a piezoelectric actuator and using high-speed camera image processing to evaluate displacements along the fibre, it becomes possible to determine intrinsic dynamic properties such as the loss factor and storage modulus. Controlled environment tests are conducted to investigate the influence of external parameters such as temperature and pressure on the measurement results. By utilizing this method, the aim is to obtain a better understanding of the damping properties of plant fibres and ultimately improve design choices for bio-based composite materials.