3D printed continuous fibre composite repair of sandwich structures

This study quantifies the effectiveness of the rapid repair of sandwich structures using 3D printed continuous fibre composite patches. The sandwich structures are representative of lightweight honeycomb structures typi-cally found in contemporary helicopters. The samples were designed to produce failure in the facesheets due to tensile or compressive stresses. This was achieved by locating the damage and subsequently repairing it on either the lower or upper facesheets. The entire repair process, including patch manufacture, was completed within two and a half hours. In all cases, the 3D printed repair restored the full load bearing capacity of the damaged structure and the ultimate strength was equal to the pristine sample configuration. These experiments give confidence that a 3D printed continuous fibre patch repair process can fully restore structural strength in damaged sandwich components.