Tailoring of bonded composite scarf joint interface for impact damage mitigation and stiffness compatibility

Abstract

A novel composite scarf joint is successfully fabricated with thermoplastic core shell microparticles incorporated into the interlaminar interface regions with a dual objective of mitigating the impact damage and improving the stiffness compatibility of the joint. The impact analysis of the joints revealed that the incorporation of microparticles led to a significant improvement of the impact load bearing capacity of joint and reduced the extent of the damage area. It is also observed from flexural tests that the microparticles reduces the stiffness of the laminate proportional to the weight fraction of the particles and thereby help design a joint adherend with controlled matching stiffness. This engineered scarf joint adherend configuration has the potential to minimise stiffness mismatch between a fatigue worn-out damaged composite part and the new scarf repair patch laminate designed for it. This shall help ensuring an easy restoration of uniform load distribution in the newly bonded composite scarf joints and repairs.

Keywords:

• Fibre reinforced composites
• Scarf joints
• Microparticles
• Impact damage
• Stiffness mismatching
• Interfaces

Acknowledgement

The authors thank The Dow Chemical Company, Singapore for their courteous assistance in donating the thermoplastic microparticles.