16 August, 2026
"Integrable e-tattoo wireless sensors for in-situ health monitoring of composite structures"
Hassan A. Mahmoud, Omar Khalifa, Yupeng Shi, Ahmed Wagih, Tareq Y. Al-Naffouri, Gilles Lubineau
Sensors and Actuators A: Physical (2026)
Composite materials are widely used in aerospace, automotive, and civil engineering because of their high strength-to-weight ratio and durability. Ensuring their reliability requires continuous monitoring to detect early damage, but conventional sensors are often bulky and intrusive, limiting practical use. In this work, we present flexible e-tattoo sensors fabricated by direct ink writing (DIW) on commercially available tattoo paper and transferred onto composite substrates. Two applications were demonstrated. First, an e-tattoo strain gauge integrated with a wireless readout circuit was applied to a glass fiber reinforced polymer (GFRP) specimen, achieving a high gauge factor of 20.7 under tensile testing. To enhance reliability, we introduced polynomial modeling of strain responses and implemented a temperature compensation strategy. Second, a chipless LC wireless sensor was embedded on GFRP-bonded joints to track adhesive curing. Resonance frequency shifts were correlated with the degree of cure, independently verified by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). These ultra-thin, lightweight, and minimally invasive sensors enable continuous, real-time monitoring without altering the mechanical performance of the host structure, offering a practical and scalable pathway for next-generation structural health monitoring (SHM) applications.
https://doi.org/10.1016/j.sna.2026.11836