Mechanical and electrical properties of hybrid honeycomb sandwich structure for spacecraft structural applications

Abstract

Multiphase composite sheets containing carbon fiber and functionalized multiwall carbon nanotubes in epoxy matrix were manufactured through compression molding technique. The loading of f-MWCNTs was varied (0.0, 0.1, 0.25 and 0.5 wt.% of epoxy matrix), while the quantity of carbon fiber was kept constant, i.e. ∼60 wt.% of the final composite in all samples. Prepared multiphase composite sheets were subjected to flexural test and the sheet offering maximum flexural strength was selected for subsequent hybrid sandwich structure manufacturing. Hybrid sandwich structure was manufactured via vacuum bagging process by bonding composite face sheet to the aluminum honeycomb core through an adhesive. Mechanical performance of hybrid sandwich structure was evaluated by performing flexural and quasi-static indentation tests, while electrical performance of hybrid sandwich structure was investigated by performing electromagnetic interference shielding effective and electrostatic dissipation tests. Optical and scanning electron microscopy was carried out for microstructural investigations. Fractography was also performed on composite face sheet after flexural test to study the underlying high flexural strength mechanism. Neat sandwich structure without functionalized multiwall carbon nanotubes addition was also manufactured and tested for comparison. Results show that hybrid sandwich structure outperformed the neat sandwich structure in all tests.