56th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference at AIAA SciTech 2015 Kissimmee, Florida, USA 5-9 January 2015

AIAA-2015-0126

Experimental Characterization of Damage Evolution in Carbon Nanotube-Polymer Nanocomposites

E. Sengezer and G. Seidel
Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061-0203, USA

Dielectrophoresis under the application of AC electric fields is one of the primary fabrication techniques for obtaining aligned carbon nanotube (CNT)-polymer nanocomposites, and is used here to generate long range structure/architecture control at the structural level. As such, effort here is focused towards characterizing the piezoresistive response of this long range structure/architecture at a concentration below percolation threshold. In this study, the electrical conductivity and the piezoresistive behavior of randomly oriented, well dispersed and long range electric field aligned single-wall nanotubes (SWNTs) in a photopolymerizable monomer blend (urethane dimethacrylate (UDMA) and 1,6-hexanediol dimethacrylate (HDDMA)) are evaluated. The electrical resistance measurements demonstrated nanocomposite strain sensing potential and were able to provide continuous assessment of damage evolution. Gauge factors both in axial and transverse direction are measured for specimens with electric field aligned 0.03 wt% SWNTs and randomly oriented, well dispersed 0.03- 0.1 wt% SWNTs under quasi static and cyclic tensile loading. Excellent piezoresistive capabilities having the potential to provide real-time structural health monitoring (SHM) and self-diagnostic functionalities are obtained at a concentration below percolation threshold for aligned specimens with SWNTs loading as low as 0.03 wt%.