Studies on Structural Damping Properties of Carbon Fiber/Epoxy Composites with Polyamide Nonwoven Fabric Modified by PVDF

As a result of the capacities of good vibration damping and structural bearing, structural damping composites had a broad application prospect in many fields, such as aeronautics and astronautics, railway transport et al. A new kind of structural damping composite was prepared by interleaving polyamide nonwoven fabrics modified by PVDF between the carbon fiber reinforced epoxy composites via co-cured method, and the damping properties and mechanical properties were studied. The mechanical properties of the co-cured composites were measured, such as flexural strength, flexural modulus, interlaminar shear strength, fracture toughness of type I and type II, and the temperature spectra of storage modulus, loss modulus and loss factor were measured by dynamical mechanical analyzer (DMA). In addition, the vibration damping characteristics were tested by single cantilever beam vibration experiments, and the microstructure and damping mechanism of the co-cured composites were analyzed by optical microscopy and scanning electron microscopy at the same time. The obtained results indicated that the damping and fracture toughness can be significantly improved by inserting PNF modified by PVDF with comparatively low falling of mechanical properties. The basic damping mechanism was that some rich resin zones with high loss factor were formed in the interlamination of co-cured composites. The obtained improvement of the loss factor of composites was as high as 150%, without degrading mechanical properties obviously.