A Competitive Study of the Static and Fatigue Performance of Flax, Glass, and Flax/Glass Hybrid Composites on the Structural Example of a Light Railway Axle Tie

The most common studies in the literature are those analyzing fatigue life under cyclic loading for flax fiber-reinforced composites. A novel type of staple fiber yarn made from flax tow with almost unidirectional fiber orientation and a quasi-unidirectional fabric was developed for composite applications. Additionally, a hybrid material made of flax and glass was produced for a demonstrator component (an axle tie of a narrow-gauge railway). For such an application, the investigation of fatigue strength is of particular importance. Therefore, the fatigue behavior of flax, glass, and hybrid flax/glass composites was investigated in the high cycle fatigue range. A total of 106 load cycles were carried out. From about 7³ to 8³ loading cycles, the flax laminate was found to have higher fatigue strength than the glass fiber-reinforced composite. The hybrid materials tend to show a higher fatigue strength than the glass type from approximately 2 × 105 load cycles. Results based on a finite element method also demonstrate better fatigue properties at an increased number of load cycles for flax-based composites than the glass fiber-reinforced component. The flax/glass component’s fatigue strength ranged between the flax values and the glass fiber-reinforced composites. Overall, the hybrid material shows significantly better static bending and impact characteristics than flax and considerably better fatigue properties than the glass fiber-reinforced composite making the hybrid material attractive for an application in an axle tie.