Thermoforming of Textile Composite Pipe Fittings

Thermoforming of braided thermoplastic composite tubes was carried out in order to clarify the mechanism of the thermoforming process for pipe fittings such as T-shape fittings, cross fittings and two-branch fittings. The composite tube was made of a cowoven braid that consists of a carbon braid and polyamide resin, and 4-ply tubes with initial fiber orientations of 18° and 26° are used in the experiment. The branch is formed with not only the fisherman's net effect but also with moving yarns along the longitudinal direction in every forming process. The results show that the deformation behavior of the braid is very complex. Therefore, fiber orientation through forming is also greatly changed. Wall thickness at the branch decreases with increasing branch height. From these results, it is found that a fitting with complex shape can be produced by thermoforming. T-shape fittings, cross fittings and two-branch fittings are achieved by this process. It is confirmed that moving yarns along the longitudinal direction plays an important role in branch forming of pipe fittings.