Influence of glass fibre reinforced polymer composite pin reinforcement on shear and dynamic behaviour of composite joint manufactured through co-cure technique

Abstract

The co-cure technique efficiently joins composite components in wings, ailerons, skins, ribs and spars in aeronautical applications. The present study investigates the effect of through-thickness reinforcement of glass fibre reinforced polymer composite pin on shear and dynamic properties of co-cured composite joints. The experimental results exhibited that through-thickness reinforcement with 2% composite pin volume significantly improved the shear strength and elongation limit by 38.4% and 102.4% compared to unpinned joints. Furthermore, composite pin reinforcement changed the catastrophic failure of co-cured joints to progressive failure due to the tougher bridging traction of composite pins. The comparison of fractured surfaces exposed that debonding, composite pin pull-out and shear fracture of pins are the major failure mechanisms involved in enhanced shear strength and progressive failure of co-cured composite joints. The experimental modal analysis avowed that through-thickness reinforcement with 2% composite pin volume improved the fundamental natural frequency of the co-cure joints, while co-cure joint reinforced with higher volume (4%) of composite pins had higher damping value due to excessive fibre damage, which increased interaction between composite adherent and adhesive.