A Three-Dimensional Strain Rosette Sensor Based on Graphene Composite with Piezoresistive Effect

Abstract

Obtaining the internal stress and strain state of concrete to evaluate the safety and reliability of structures is the important purpose of concrete structural health monitoring. In this paper, a three-dimensional (3D) strain rosette sensor was designed and fabricated using graphene-based piezoresistive composite to measure the strains in concrete structures. The piezoresistive composite was prepared using reduced graphene oxide (RGO) as conductive filler, cellulose nanofiber (CNF) as dispersant and structural skeleton, and waterborne epoxy (WEP) as polymer matrix. The mechanical, electrical, and electromechanical properties of RGO-CNF/WEP composite were tested. The results show that the tensile strength, elastic modulus, and conductivity of the composite are greatly improved by the addition of RGO and CNF. The relative resistance change of composite films demonstrates high sensitivity to mechanical strain with gauge factors of 16-52. Within 4% strain, the piezoresistive properties of composites are stable with good linearity and repeatability. The sensing performance of the 3D strain rosette was tested. The measured strains are close to the actual strains of measure point in concrete, and the error is small. The RGO-CNF/WEP composite has excellent mechanical and piezoresistive properties, which enable the 3D strain rosette to be used as embedded sensor to measure the internal strain of concrete structures accurately.

High-Performance Multidirectional Flexible Strain Sensor for Human Motion and Health Monitoring

“…Depending on the angle of combination between individual sensors, it can be categorized into 45°, 60°, and 120° strain rosettes. Strain rosettes possess the capability to simultaneously measure both the magnitude and direction of strain, commonly utilized for detecting the strain in building structures to evaluate safety and reliability. − Alternatively, they can be employed to assess the strain state within a device, enabling health monitoring of the device. , The remarkable research outcomes are extensively applied, yet the limited ductility of traditional materials like metals restricts their use in monitoring human skin or joint motion. To address the requirements of wearable devices and human−machine interaction, there is a critical need to develop flexible sensors capable of measuring multiple strains with high ductility.…”