A New Real-Time SHM System Embedded on Raspberry Pi

This paper outlines the development of a real-time monitoring system, which incorporates hardware, software and database, applied to structural health monitoring (SHM). The system was conceived, designed, implemented and embedded on Raspberry Pi 3 (RP). With the need for reliability and information being provided in real time (IoT), RP has tightly integrated into the SHM field. To accomplish that, we developed an acquisition system based on Pmod IA (AD5933) along with the multiplex 4066, used to switch among the piezoelectric transducers. Furthermore, a real-time web application was developed to manage the acquisition system, integrate hardware with software and store the data collected in a dedicated NoSQL database. To perform excitation and get the structural response signals, experiments were carried out based on the electromechanical impedance technique by using three PZTs glued into an aluminium structure. Sinusoidal excitation signals, ranging from 20 kHz to 30 kHz with an amplitude of 2 V, were applied to the host structure. Overall, the reference system presented higher sensitivity for the RMSD metric, whilst the proposed system showed more relevance for damage detection via CCDM. Despite being implemented in low-cost hardware, the developed system identified structural failures with good reliability, being advantageous from both financial and dimension standpoints.