On the Dynamic Performance of Flax Fiber Composite Beams Manufactured at Different Relative Humidity Levels

LI, HUAIZHONG; FRANCUCCI, GASTON; HALL, WAYNE; MOUDOOD, ABDUL; ÖCHSNER, ANDREAS

Journal of Natural Fibers

Taylor and Francis

Año: 2020 vol. 17 p. 598 - 608

1544-0478

Development of environment-friendly natural fiber composites has been arecent trend. However, due to the fact that natural fibers permit high levelof moisture absorption from the surroundings, it can lead to weak bindingsand degradation of composite properties. This paper presents an experimentalstudy on the dynamic performance of flax fiber composite beamsmanufactured at different relative humidity (RH) levels. Five types of flaxfiber-reinforced composite materials were made under different RH values,i.e., dry, 35%, 50%, 70%, and 95% RH, and beam samples were preparedusing the composite. Impact hammer testing was conducted to measurethe natural frequencies and damping of the beams. It was found that forthe first three modes, while the resonant frequencies are very close for mostsamples, there is a clear drop of frequencies for the composite fabricated at95% RH. Along with an increase of the RH level, the damping ratios for allthe three modes have reported a slight increase, but the variation is notsignificant.