Electrical response of carbon nanotube reinforced nanocomposites under static and dynamic loading
The electrical response of multi-wall carbon nanotube (MWCNT) reinforced epoxy nanocomposites under quasi-static and dynamic compressive loading is experimentally investigated. The objective of this project was to study the electrical response of CNT-reinforced nanocomposites under mechanical loading where the carbon nanotubes are used to create an internal sensory network within, capable of detecting important information such as strain and damage. Experimental techniques were developed to effectively obtain the bulk resistance change of the nanocomposite material while subjected to quasi-static and dynamic loading. A combination of shear mixing and ultrasonication was used to fabricate the low resistance nanocomposite material. The fabrication process parameters and the optimum weight fraction of MWCNTs for generating a well-dispersed percolation network were first determined. A screw-driven testing machine, a drop weight tower, and a split Hopkinson pressure bar (SHPB) apparatus were utilized to load the specimens. Absolute resistance values were measured with a high-resolution four-point probe method for both quasi-static and dynamic loading. In addition to measuring the percentage change in electrical resistance, real-time damage was captured using high-speed photography. The real-time damage was correlated to both load and percentage change in resistance profiles to better understand the electrical behavior of CNT reinforced nanocomposites under mechanical loading. The experimental findings indicate that the bulk electrical resistance of the nanocomposites, under both quasi-static and drop weight loading conditions, initially decreased between 40%–60% during compression and then increased as damage initiated and propagated. Similarly, a 65%–85% decrease in resistance was observed when the nanocomposites were subjected to SHPB loading. Damage initiation and propagation was also captured by the resistance measurements owing to the ability of the CNTs to be used to provide the sensing capability within the nanocomposites.
Nicholas J Heeder,
"Electrical response of carbon nanotube reinforced nanocomposites under static and dynamic loading"
Dissertations and Master's Theses (Campus Access).