Finite Element Modeling of Piezoresistivity in Graphene Coated Glass Fiber Reinforced Polymer Composites

Abstract

Structural Health Monitoring (SHM) of composite materials is a challenging task due to their heterogeneous structure and complex failure behavior. Traditional methods for SHM have certain limitations, such as localized measurement, computational processing costs, sensitivity to environmental factors, and the need for high-resolution cameras. Recently, materials like carbon nanotubes (CNTs) and graphene, known for their excellent electrical and mechanical properties, have opened new research avenues for SHM sensors development. However, current research largely focuses on costly experiments. Finite element modeling (FEM) of SHM systems using these emerging materials is not yet widely explored. This study presents a novel approach to modeling the electrical response of sensors embedded in fiber-reinforced polymer composites using FEM at the macro scale. Initially, validation studies were conducted using the Abaqus simulation tool, where a graphene sheet is coated on a glass fiber reinforced polymer (GFRP) composite. Simulations are carried out for loadings at strain rates of 0.2 mm/min, 2 mm/min, and 20 mm/min. The mechanical behavior of GFRP is assumed to be elastic-plastic, and the electrical response, coupled with the mechanical response through the strain of the graphene sheet, is obtained using the UVARM subroutine. Root mean squared error (RMSE) of 3.574, 0.889, and 1.315 in fractional change in resistance (FCR) for 0.2 mm/min, 02 mm/min, and 20 mm/min, respectively, which is significantly small, demonstrating a good correlation between the simulations XII and experiments. The study is further extended to embed the graphene sensor in unidirectional GFRP with different fiber orientations. The electro-mechanical responses are plotted for each system of graphene-coated laminates with different fiber orientations, providing deep insight into monitoring deformation in unidirectional GFRP composites. The FCR at damage is 29%, 15%, and 30% for graphene-coated GFRP laminates with fiber oriented at [0◦ ]4s, [90◦ ]4s, and [0◦ , 45◦ , −45◦ , 90◦ ]s, respectively. This study provides a direction for future microscale FEM modeling of piezoresistivity in graphene-coated composite laminates.