Complex shape forming of flax based woven fabrics. Analysis of the yarn tensile strain during the process.

摘要

A flax fibre plain weave fabric has been used to form a complex tetrahedron shape. The global shape has been obtained. Even if no apparent defects are visible when observing the yarns, the strain of the tightest yarns of the preform has been measured and compared to the biaxial strains of the fabric determined independently of the process. The results show that the strains in the yarns close to the triple point of the shape (top of the tetrahedron) are higher than the strain at failure. This could lead to local lack of fibre density and to possible zones of weakness for the composite part. It is therefore necessary to increase the tensile performances of the yarns constituting the fabric.