Evaluating the Suitability of MEMS-Based Monitoring Systems: A Comparative Study of Performance and Applicability

Distributed monitoring systems that rely on edge-devices are becoming popular in Structural Health Monitoring applications. Typically, these solutions integrate a micro-controller unit and MEMS sensors in the same node, thus creating a smart sensing node, managing measurements, preliminary data analysis and connection between edge, gateway and cloud. Although these systems offer benefits such as ease of installation, redundancy, and IoT integration, challenges such as data synchronization and sensitivity variations can hinder the analysis of dynamic behavior of a structure, including natural frequency tracking and vibratory energy evaluation. Consequently, the robustness of modal parameter extraction through operational modal analysis may be questioned in such setups. This paper demonstrates that reliable estimation of modal parameters using MEMS-based systems is achievable when their metrological performance and application-specific factors are carefully considered. A validation methodology compares the performance of MEMS-based systems with traditional centralized high-performance systems using piezoelectric accelerometers and synchronous acquisition to measure the dynamic behavior of the same structure. Two case studies highlight the approach: a pedestrian bridge subjected to environmental excitation and a prestressed reinforced concrete girder bridge tested under controlled dynamic loads and operational traffic conditions. The comparative analysis evaluates the advantages and limitations of both systems, providing insight into their respective performance in SHM applications. The results show that MEMS-based systems, despite their inherent limitations, can achieve robust and reliable results, emphasizing the importance of application-aware design and calibration in distributed SHM systems.