Development and Application of Nanocomposites Sensors for Structural Health Monitoring

• Grant number: 25/01541-2
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: June 01, 2025
• End date: August 31, 2026
• Field of knowledge: Engineering - Mechanical Engineering - Mechanics of Solids
• Principal Investigator: Samuel da Silva
• Grantee: Eduardo Preto
• Host Institution: Faculdade de Engenharia (FEIS). Universidade Estadual Paulista (UNESP). Campus de Ilha Solteira. Ilha Solteira , SP, Brazil

Abstract

A novel approach is proposed for structural health monitoring (SHM) using nanocomposites designed explicitly to detect torque variations in bolted joints and crack propagation in metallic structures. Two resistive nanocomposite sensors were developed and tested to correlate electrical resistance changes with the torque applied to bolted joints and crack growth. This allows for static measurements for structural damage analysis instead of traditional methods that typically require dynamic analysis. The first sensor applied to a bolted joint, consists of a flexible nanocomposite with a natural rubber matrix incorporating carbon nanotubes and carbon black for conductivity. In this sensor, deformation caused by bolt torque changes the electrical resistance. The second sensor comprises polyvinyl butyral (PVB) with indium tin oxide (ITO) nanowires, providing a rigid mechanical film. The resistive effect in this sensor arises from the rearrangement of nanowires under deformation, which alters electrical resistance; thus, its application in crack monitoring is based on the sensor's failure in tandem with the structural crack. The sensors show potential application due to their simplicity in measurement and analysis. In addition to functioning as on-off sensors, they enable correlation of the resistive effect with other variables, such as torque variation and crack length, expanding their utility in structural health monitoring applications.