The effective parameters on shear properties of sandwich panels with glass fibers-vinyl ester composite skin and polyvinyl chloride core

In this study, the effects of adhesive type (Epon 828 and Araldite EA 1103), the overlapping area (12.5 and 25 mm), and the surface treatment of the polymer composite on the shear behavior of the sandwich panels with a foam core of polyvinyl chloride (PVC) C7075 and a polymer composite skin (glass fibers-vinyl ester) were investigated by finite element simulation and experiment. The results revealed that the sample with Epon adhesive exhibited higher shear strength and lower strain percentage value compared to the sample containing the Araldite adhesive. The samples with an overlapping area of 12.5 mm showed higher shear properties compared to those with a 25 mm overlapping area which is due to the presence of more bubbles and imperfections on the overlapping surface. Due to increased contact area and penetration of the adhesive into the porosities, surface-modified polymer composites with 100-grit sandpapers exhibited higher shear properties in comparison with those surface modified with 60-grit sandpapers. Also, the investigation of the fracture mechanism showed that the two mechanisms of the adhesive fracture and the rupture of the PVC foam led to the destruction of the sandwich panel. Since the foam rupture mechanism overcame the adhesive fracture, the shear properties of the sandwich panel were increased. The results showed that there was a good agreement between the experimental and simulation results.