Ricerc@Sapienza

Structural health monitoring (SHM) has assumed an increasingly significant role in assessing safety and integrity of load-bearing composite materials in the civil and aerospace engineering. Glass and carbon fiber reinforced composites (FRC) have emerged as common replacement for metals in many structural components due to their high strength-to-weight ratio and fatigue resistance, although their failure mechanisms are complex and damage detection challenging. Therefore, several damage detection and monitoring methods have been investigated with different degrees of success. In particular, promising results have been obtained with techniques based on the measurement of the damage/strain-induced change in the electrical properties inherent to composite material or to an ad-hoc applied conductive coating.
In this work our objective is to produce a novel nanocomposite functional paint to be used as high sensitive piezoresistive coating for imaging of strain map and damage in composite structures through the electrical resistance tomography method (ERT). ERT is a sophisticated non-invasive imaging technique that uses electrical measurements made from a set of electrodes located along the periphery of the sensing skin to reconstruct the conductivity spatial distribution. The developed sensing skin will consist of a thin film of multilayer graphene nanoplateletes (MLG)-filled polymer that will be applied directly to the surface of the material to be monitored with a simple spray coating technique. The properties of the paint will be optimized by feedback from the morphological characterizations, adhesion tests, rheological and electrical measurements. Then, a 2D spatially distributed sensing skin, able to map damages and deformations over large areas, will be deposited on a FRC plate. The electrical measured data will be processed with an open source ERT matlab code (EIDORS) demonstrating the feasibility and potentiality of the proposed SHM system.