Influence of lightweight pumice on low velocity impact response of carbon fiber reinforced pumice epoxy core sandwich composites

The present study investigates novel carbon fiber sandwich composites reinforced with lightweight pumice. Four types of sandwich composites are manufactured by varying the pumice content in 0, 3, 6 and 9 wt.%. Composites are manufactured by casting the core first using an open mold, and the sandwich composites are prepared using a closed mold. Particle size analysis reveals the average size of pumice particles to be around 62.44 μm. Density of the sandwich composites decreases by 7% with an increase in the pumice particle content from 0-9 wt.%. The impact resistance of the sandwich composites increased with the increase in pumice content up to 6 wt.% (CP-0, CP-3 and CP-9) and decreased at 9 wt.% (CP-9). The energy absorbed by CP-0, CP-3, CP-6 and CP-9 was measured as 13.27, 24.69, 31.65 and 8.83 J, respectively. A notable increase of 86% and 138% in energy absorption was observed with 3% and 6% pumice content compared to CP-0. Compression after impact of impact-tested specimens reveals a compressive strength of 31, 35, 39 and 43 MPa for CP-0, CP-3, CP-6 and CP-9, respectively, indicating a 26% and 39% enhancement of CP-6 and CP-9 composites compared with CP-0 composites. Scanning electron micrographs of specimens after compression were performed to analyze the structure-property correspondences. Finally, numerical simulations to validate the conclusions of the study were performed.