Study of the Effect of Patch Bonded Surface Area and Shape on Flexural Strength of Glass/Polyester Composite using External Bonded Repair Technique

The objective of this project is to investigate tbe effectiveness of patch surface
area and shape on flexural strength of the composite material. The material under study
is glass/polyester composite and it is prepared by using hand lay-up technique. The
patch shapes under investigation are square and octagonal. Five different patch surface
areas were prepared varying from 2mm until 8mm. The parent laminates were damaged
by drilling a standard 8.42mm diameter hole in the middle of it as artificial damage. A
piece of composite material is tben attached to the original primary composite structure
using an adhesive to restore the original performance of tbe composite. The flexural test
is conducted under ASTM Standard D790 by using three point loading system.
However, from the results obtained from the test, it was found that the flexural yield
strength value is more relevant to be calculated rather than flexural strength due to the
constraints of the test specimen.