The influence of localized repair techniques on the indentation performance of delaminated glass-fiber/epoxy laminates

This study attempts to restore the quasi-static indentation (QSI) performance of damaged woven and chopped glass-fiber/epoxy laminates by applying different repair methods which are low cost and easy to apply. Four different repair techniques were applied to the delaminated glass-fiber/ epoxy Laminates. Compared to the pristine specimen, the traditional patch repair was capable of restoring 39.5 % and 48.98 % in terms of maximum load capacity for both woven and chopped laminates. Injection repair after rebounding the surface to its original geometry, by applying heat 90 ◦C and pressure 20 kg, has 71.13 % and 56.87 % efficiency of maximum load recovery for both W and C specimens. Two different stitching repair patterns were developed to the damaged zone in order to study to what extent this method of stitching would restore the original load capacity. Every pattern reveals a significant percentage of restoring the original indentation performance. The first stitching pattern results 87.02 % and 82.32 % for woven/epoxy and chopped/epoxy composites, respectively. The other pattern shows distinctive powerful ability in restoring maximum load capacity as 101.7 % and 98.33 % for woven/epoxy and chopped/epoxy composites, respectively. Also, the efficiency of the repair techniques in terms of the absorbed energy was investigated during this work. Scanning Electron Microscopy (SEM) and Energy Dispersive Xray Spectroscopy analysis are performed to indicate and quantify the subsurface delamination and to confirm the restoration at the fiber/matrix interface.