Experimental Investigation of Core Shear Properties and Facing Sheet Fracture Stress of Spherical Sandwich Structure

Abstract

In this study, two different models interlock and stagger spherical structure were designed and developed by using molding process. The matrix used for fabrication is vinyl ester and the woven glass fiber cloth of grade 300 and chopped strand mat (CSM) of 450 grades are used as reinforcement. The size of the model is 330 × 44 mm. Two pitch distances of 24 and 32 mm were selected as spacing between the centers of spheres. The shear stress of core and the fracture stress of facing sheet were tested using three-point bend test. From the test result, it is understood that the interlock model (CSM 32 mm) possess a high shear stress of core having a value of 465 kPa, which is less or more equivalent to honeycomb structure and fracture stress of facing sheet of 37.29 MPa. Whereas the stagger model with woven 32 mm pitch shows low core strength of 69 kPa and fracture stress of facing sheet of 5.58 MPa.