Fibre misalignment in filament wound tubes

Glass fibres/epoxy resin composites were produced by filament winding as circular section tubes. The composites were produced with 6, 12, and 24 layers. They were sectioned and examined for fibre misalignment in plane and out of plane. The angular deviations were significant and it was found that in-place misalignment was more pronounced than out of-plane. The composites were tested in three-point bending as ring type specimens. The obtained results for radial strength could be correlated with the angular deviations, giving the decrease in radial strength with increasing out of plane and in plane deviations. The observed effect is believed to be due to the defects in the resin, as with the larger angular deviations the larger volume of resin between fibre layers is subjected to the maximum interlaminar tensile stresses.