Experimental investigation of mechanical and modal properties of Al2O3 nanoparticle reinforced polyurethane core sandwich structures

In this study, experimental mechanical and modal analyses of nano-Al(2)O(3 )ceramic powder reinforced polyurethane foam core sandwich composites was carried out along with the investigation of vibration, buckling and compression responses. The reinforcement ratio of Al2O3 ceramic powder was varied from 0 to 10 % by weight. The morphological effect of Al2O3 powder reinforcement on the polyurethane microstructure was also investigated by benefitting from an optical microscope. Significant improvements in the damping response and the buckling behavior of the Al2O3 sandwich specimens were observed. In this context, a 38.3 % increase in the damping ratio was observed for 2% Al2O3 reinforced specimens compared to the neat specimens and the specimens with 1% and 3% Al2O3 reinforcement showed 31.4 % and 26.8 % increase, respectively. Similarly, a 6% increase in the buckling peak load was observed for specimens with 5% reinforcement compared to the neat specimens. However, the compression peak load was observed to decrease linearly with an increase in the reinforcement ratio for all the reinforced specimens. TG-DTG, DSC and FTIR analysis of PUF cores with different reinforcement ratios were also performed within the scope of this study. It was observed in the TG graphs that the weight loss decreased with an increase in the reinforcement ratios. The glass transition temperatures of all the PUF core specimens were found by performing DSC analyses whereas, the structural bonds were detected by using the FTIR technique. Composite foam cores showed the existence of a dominant polyurethane structure.