Multifunctional Nanocomposites With High Damping Performance for Aerospace Structures

Polymer matrix composites with reinforcement of carbon nanofibers and carbon nanotubes in the form of paper sheet have shown significant vibration damping improvement compared to pure matrix materials. The large specific area (1000 m²/g) and aspect ratio (>1000) of carbon nanotubes and nanofibers promote significant interfacial friction between carbon nanotubes/nanofibers and a polymer matrix, which causes much higher energy dissipation in the polymer matrix. In this study, a unique concept of manufacturing nanocomposites with carbon nanotube/nanofiber based nanopaper sheets for vibration damping applications has been explored. The new approach includes making carbon nanopaper sheet by the filtration of well-dispersed carbon nanotubes and carbon nanofibers under controlled processing conditions. Subsequently, carbon nanopaper sheets are integrated into composite laminates as surface layer using the vacuum assistant resin transfer molding (VARTM) process. To compare the damping property of laminates constituted by different fibers, three kinds of fibers, including glass fiber, basalt fiber, and carbon fiber are used. For the comparative study, the vibration damping ratios of samples with and without carbon nanopaper sheets are determined. To identify the damping characteristics of each specimen, the Frequency Response Function (FRF) was estimated by a pair of piezoceramic patches: one as an actuator to excite the specimen and the other as a sensor to detect the induced vibrations. From the FRF, the damping ratio of the specimen at each modal frequency of interest was calculated. The experimental results clearly show a significant improvement of vibration damping properties of the nanocomposites plates. This research demonstrates vibration damping enhancement of a polymer matrix via incorporation of carbon nanopaper sheets and provided basic understanding of the damping characteristics for the optimal design and fabrication of high performance damping composites, which have the potential to be used as structural components for different applications.