Three-point bending performance of circular-shaped core foam-filled sandwich panels reinforced with carbon fibers and silica nanoparticles

Abstract This paper presents a novel approach to designing and manufacturing a composite sandwich panel with circular-shaped core. The sandwich panel is reinforced with silica nanoparticles (SNPs) and filled with polyurethane (PU) foam. The mechanical properties of the sandwich panels are then evaluated through a three-point bending (TPB) test. The study investigates the impact of various parameters, including the core’s length and height, the weight percentage (wt.%) of SNPs, and the PU foam, on the structure’s flexural strength. Additionally, the fracture surface of specimens is studied by scanning electron microscopy analyses. In order to validate the findings, a TPB test of the sandwich panel was simulated using ABAQUS software. The obtained results were then compared to the experimental data, revealing a favorable level of agreement between the two. The research findings indicate that incorporating SNPs within a specific range significantly improves flexural strength. Specifically, adding SNPs up to 3% results in an approximate 37% increase in flexural strength. However, the addition of 4 wt.% SNPs causes a decrease of about 13% in the strength of the sandwich panel. Furthermore, the geometry of the core plays a crucial role in controlling the flexural strength and rigidity of the panel. Increasing the core length and height decreases flexural strength by 52% and 31%, respectively. Moreover, the study reveals that the inclusion of PU foam in the sandwich panel, despite a slight increase in weight, significantly enhances flexural strength by about 54% and delays its ultimate failure. Eventually, the hybrid specimen exhibits a flexural strength approximately 70% greater than the pure foamless sandwich panel.