Folding endurance of continuous silicon carbide fibres: A comparative study

The limited folding resistance of continuous silicon carbide (SiC) fibres hinders their application as flexible, foldable materials. With this objective in mind, the folding endurance and damage properties of the second (2nd) and third (3rd) generation continuous SiC fibre tows were investigated through repeated folding tests, optical microscope observation and tensile tests. These SiC fibre tows were disassembled from two-dimensional (2D) SiC fibre braided fabrics with varying braiding angles. The braiding process can alleviate the force on fibre tows during the textile forming process. The investigation of damage mechanisms and analysis of force conditions are instrumental in optimizing structural parameters. The research findings suggested that, in comparison to the 3rd generation continuous SiC fibres, the 2nd generation SiC fibre tows demonstrated higher resistance to repeated folding. In contrast, the 2nd generation fabrics exhibited slightly lower folding endurance values. After repeated folding, the SiC fibre tows in fabrics showed the highest strength losses near the braiding angle of 37.8° to 38.3°. In comparison, the SiC fibre fabric demonstrated the lowest folding endurance values (approximately 760 times) near the braiding angle of 41° to 42°. Considering factors such as folding endurance value, the strength loss rate of fibre tows and fabric strength loss rate, it can be concluded that SiC fibres in fabrics with large braiding angles exhibit optimal performance in terms of folding endurance.