Design Methodology for Braided Composite Tubes. 1st Report. Bending Properties.

Abstract

The design methodology for braided composite tube was proposed. The weaving structures such as fiber orientation angle and crimp ratio of fiber largely affect the mechanical properties of braided composites, thus the analytical model has to represent faithfully the weaving structures. Therefore the analytical procedure involved the use of models from micro model to macro model. This method was applied to estimate flexural rigidity and initial fracture stress of braided tube under bending load. The flexural rigidity decreased with increase of fiber orientation angle, which was the angle formed between the fiber bundles and the fabric axis. The flexural rigidity was enhanced by middle-end-fiber and the effect varied with the location of middle-end-fiber. The position at which initial fracture occurred was changed depending on the fiber orientation angle. In the case of small fiber orientation angle the initial fracture stress depended on the strength of the cross resin element, so that the initial fracture stress was not always enhanced by the middle-end-fiber.