Development of a Multifunctional Stretchable Sensor Network for Smart Structures

Abstract

Smart structures revolutionize the traditional manned systems and challenge the structural health monitoring (SHM) field from a completely new perspective. Advanced sensing technology enables highly intelligent systems by embedding sensor networks into composite materials for smart structures such as fly-by-feel flights and intelligent robots. In this paper, we present a highly stretchable network with multifunctional sensor nodes microfabricated on a flexible polymer substrate. For the first time, we are capable of integrating three types of sensors with their appropriate materials into one single network. 6 platinum resistance temperature detectors (RTDs), 27 constantan strain gauges (SGs) and 8 lead zirconate titanate piezoelectric transducers (PZTs) with their unique patterns are distributed over the entire network. Finite element modeling has been performed to analyze the stress distribution along the node-wire connections during the stretching process in order to minimize nodal rotations. By taking advantage of a serpentine wire design, the network can be expanded 700% in area while maintaining high yield and low variation. A series of sensor characterizations have been conducted to validate the functionality of RTDs, SGs and PZTs. It is worth mentioning that the sensitivity of the RTD is 0.1 V/°C and the minimum detectable strain of the SG is as low as 2.26 με. The multifunctional sensor network will be embedded into a composite wing to provide real-time aeroelastic feedbacks in a wind tunnel