Characterization and Implementation of the Anisotropic Elastoresistivity of Carbon Nanotube-based Thin Film Strain Sensor for Structural Health Monitoring with Electrical Impedance Tomography

The field of developing new sensors and new technologies for monitoring imperfections and damages are of major interest to the current aerospace and automobile industries. Among many of them, carbon nanotube (CNT)-embedded polymeric thin films are one of the ideal solutions to be built-in lightweight structures for in situ health monitoring. Their unique electrical properties in responding to deformation make them an appropriate candidate for strain sensing applications for structural health monitoring (SHM). In combination with an electrical impedance tomography (EIT) analysis, a spatial map of the resistivity change can be used to identify damage within an inspected area. This thesis focuses on a detailed characterization of an inkjet printed CNT-thin film, investigating its elastoresistive properties with respect to its strain-state. The piezoresistive characterization of a semiconductive materials is used to perform a tensor analysis of the thin film’s elastoresistivity. Moreover, the characterized elastoresistivity matrix is implemented in the analysis of EIT results, which was performed over a notched specimen under uniaxial tensile load with CNT thin film printed. In addition, a digital image correlation (DIC) analysis was performed over the same specimen by using the printed CNT thin film as a speckled pattern, and the results were compared with the EIT results and a finite element method (FEM) results.