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

ABSTRACT

Development of environment-friendly natural fiber composites has been a recent trend. However, due to the fact that natural fibers permit high level of moisture absorption from the surroundings, it can lead to weak bindings and degradation of composite properties. This paper presents an experimental study on the dynamic performance of flax fiber composite beams manufactured at different relative humidity (RH) levels. Five types of flax fiber-reinforced composite materials were made under different RH values, i.e., dry, 35%, 50%, 70%, and 95% RH, and beam samples were prepared using the composite. Impact hammer testing was conducted to measure the natural frequencies and damping of the beams. It was found that for the first three modes, while the resonant frequencies are very close for most samples, there is a clear drop of frequencies for the composite fabricated at 95% RH. Along with an increase of the RH level, the damping ratios for all the three modes have reported a slight increase, but the variation is not significant.

摘要

开发环境友好型天然纤维复合材料是近年来发展的趋势。然而，由于天然纤维允许高水平的水分从周围吸收的事实，它可以导致弱粘合和复合性能的劣化。本文研究了在不同相对湿度（RH）水平下制备的亚麻纤维复合材料梁的动态性能。在不同的RH值下制备了五种类型的亚麻纤维增强复合材料，即干、35%、50%、70%和95%RH，并用复合材料制备了梁试样。冲击锤试验进行了测量的固有频率和阻尼梁。结果发现，对于前三种模式，在大多数样品的共振频率非常接近的情况下，在95%RH下制备的复合材料的频率明显下降。随着RH水平的增加，所有三种模式的阻尼比都有轻微的增加，但变化不显著。

KEYWORDS:

• Composite material
• natural fiber
• dynamics
• modal testing
• relative humidity
• flax fiber

关键词:

• 复合材料
• 天然纤维
• 动力学
• 模态试验
• 相对湿度
• 亚麻纤维