Material integrated sensors for an optimal baseline selection on a wireless SHM network

The successful evaluation of both temperature and capacitive humidity sensors integrated in Fiber-Reinforced-Polymers (FRP) is presented in this work. There is a need to obtain a set of baselines for compensation on a Wireless Sensor Network (WSN) in Structural Health Monitoring (SHM). The need for compensation methods arises from the environment's influence on the structures. In an SHM system working under the principle of acoustic Lamb-waves, excited and detected by piezo elements; humidity and high temperatures can lead to moisture up-take in the polymer matrix, altering the Lamb-wave propagation. Hence, here it is demonstrated that integrated sensors can be used to monitor the structure for water up-take and in the long run, even aging. The results will aid selecting the appropriate baselines to calibrate the in-situ measurement.