ULTRA-LIGHTWEIGHT CFRP CORES MADE BY INTERLOCKING METHOD: FABRICATION AND EVALUATION

JUAN PABLO VITALE; GASTON FRANCUCCI; ARIEL STOCCHI

Munich

Conferencia; 17th European Conference on Composite Materials; 2016

Sandwich structures are widely used in applications were low weight and highbending strength and stiffness are required, such as the transportation andaerospace industry. Sandwich panels consist of a thick layer (core) intercalatedbetween thin-stiff layers (skins). The development of high performance cores, such as 3-dimensional carbon fiber reinforced polymer (CFRP) cores allows optimizing the strength (and stiffness) to weight ratio of the panels. This coreconfiguration combines the advantages of 2-dimensional honeycombs and hollow cores. In this work, carbon fiber cores were obtained using an interlocking method. Flat composite plates were manufactured by the vacuum infusion (VI) technique using bidirectional woven carbon fiber fabrics and epoxy resin. These laminates were cut by water-jet into three different geometrical patterns that were interlocked and bonded together following a square pattern. In this way, ultra-light weight cores were obtained with densities lower than 48kg/m 3 .The mechanical performance (compressive and shear strength) and the failuremodes of the three different cores were evaluated. Results were compared tothose predicted by an analytical model and FEM (Finite Element Method)analysis. The expected performance of the cores was substantially higher than the obtained during the mechanical tests. This was attributed to manufacturing imperfections (mainly voids) in the composites comprising the core walls that were neglected in the models.