Experimental investigation on flexural behaviour of spherical core sandwich structure

The flexural behaviour of a novel spherical core sandwich structure made up of glass fibre reinforced plastic is investigated. The core orientation is modified into four different types called as regular, inverted, interlock and stagger. Vinyl ester resin is used as a matrix and two glass fibre reinforcements, namely chopped strand mat and woven fabrics, are used. The spherical core diameter is taken as 16 mm, whereas 24 and 32 mm are taken as the pitch distances. Three-point and four-point configurations are taken for the flexural tests. The flexural stiffness of these 16 different types of cored structures is found as per the ASTM D7250 standard. The failure patterns are analysed as per the ASTM C393 standard. In both the loading configuration of interlock model with 32 mm pitch, distance shows an improved flexural stiffness. Most of the failures are observed to be debonding between the facing sheet and the core, whereas in the interlocking model with 32 mm pitch, the failure is due to the fracture of the facing sheet.