Abstract
The internal damage process of carbon fiber stitched carbon fiber reinforced plastic composite laminates was investigated through both experimental observation and numerical analysis. The damage process of the stitched laminate was compared with that of the unstitched one. From the experimental observation results, it was shown that delamination was suppressed by the stitch threads, but the ultimate strength was lower due to the stitching. A finite element analysis was carried out in order to explain the experimental features. A novel FE model was proposed, where the internal damage was modeled by using specially developed elements. By analyzing this model, it was made clear that the reason of the suppression of the delamination was that stitch threads suppressed the mode-I deformation of the delaminated layers.
