Interface properties of foam-core sandwich structures fabricated by VARI process

Two methods, i.e. laying resin bonding film at the face-core interface and using foams with well-arranged holes, were proposed aiming to improve the face-core interface properties of sandwich panels fabricated by vacuum assisted resin infusion(VARI) process. The possibility and benefits of these methods were investigated. Moreover, the influence of the existence of resin film and its thickness and density of holes in the foam core were investigated by non-destructive test, three-point bending test, computer simulation and interface microstructure observations. The analysis results indicate that sandwich structures without resin film achieve the highest face-core interface strength, while with 0.5 mm resin film show the fewest defects in non-destructive testing(NDT). When the film is as thick as 2 mm, the interface properties will deteriorate. Well-arranged holes in the foam core can promote infiltration process through the whole thickness of the sandwich construction, resulting in good interfacial and high stiffness.