Peel strength studies on sandwich composites

Abstract

Sandwich composites are deemed to be the future skin of aircraft. Newer aircrafts such as the Boeing Dreamliner have been adopting aircraft skins composed of up to 50% of composite structures. However, the aviation industry is hesitating to use 100% composite structures due to the many problems sandwich composites have, one of which is its peel strength.

In this project, many different types of sandwich composites have been fabricated. 4 different variations have been identified to affect the peel strength of a sandwich composite; mainly the facesheet, the core diameter, the core thickness and the influence of aerogel. Upon fabrication, the peel strength of the sandwich composites were tested and investigated using a climbing drum peel test.

From the investigation, it was observed that sandwich composites with facesheets of larger cross weave have higher peel strength. The larger consistent surface contact that was uninterrupted by the cross weave enabled stronger bonding.

The honeycomb core dimensions played an important role in increasing the overall sandwich composite’s peel strength. Increasing the honeycomb core diameter or thickness only served to decrease the peel strength of the sandwich composite.

Lastly, the aerogel influence on sandwich composite turned out to be negative. Drastic decrease in peel strength was noted in samples filled with aerogel. This was due to the adhesive being wasted on the aerogel particles, where there is no proper bonding between the aerogel and the sandwich composite.