Influence of Cell Size on the Core Shear Properties of FRP Honeycomb Sandwich Panels

This article deals with the influence of cell size on the core shear modulus and shear strength of fiber-reinforced plastic (FRP) honeycomb core sandwich panels. A relationship between the cell size and core density has been established for the honeycomb core made by matching the mold method. The cell size ranges from 8 to 25mm, with the cell height kept constant at 8 mm. The sandwich panels are prepared with facings made of Bi-woven glass E fabric, using the vacuum bagging technique. The core shear modulus G and flexural stiffness D of the sandwich panels have been experimentally determined as per the ASTM C393. The shear strength of the sandwich panel has been determined using a short beam bend test. A correlation has been established between the core density and the core shear modulus as well as the core density and the core shear strength. The results have been compared with those of sandwich panels made with polyurethane (PUR) foam as the core material of different densities. It has been found that for the given core density the core shear modulus of the FRP honeycomb core is far higher than that of PUR foam. However, the shear strength of the FRP honeycomb sandwich panels is only marginally higher when compared to that of PUR foam.