Structural Health Monitoring system with Narrowband IoT and MEMS sensors

TL;DR

This paper presents a low-cost, long-range wireless sensor system using MEMS accelerometers and NB-IoT for continuous structural health monitoring of civil infrastructures, enabling multi-year operation and accurate modal analysis.

Contribution

It introduces a novel, energy-efficient wireless sensor node with long-range connectivity and validated accuracy for structural health monitoring, not previously available in commercial or research devices.

Findings

Sensor node achieves over ten years of operation with a large battery.

Energy-neutral operation possible with a small solar panel.

Measurement accuracy suitable for modal analysis, with only 0.08% difference from high-precision instruments.

Abstract

Monitoring of civil infrastructures is critically needed to track aging, damages and ultimately to prevent severe failures which can endanger many lives. The ability to monitor in a continuous and fine-grained fashion the integrity of a wide variety of buildings, referred to as structural health monitoring, with low-cost, long-term and continuous measurements is essential from both an economic and a life-safety standpoint. To address these needs, we propose a low-cost wireless sensor node specifically designed to support modal analysis over extended periods of time with long-range connectivity at low power consumption. Our design uses very cost-effective MEMS accelerometers and exploits the Narrowband IoT protocol (NB-IoT) to establish long-distance connection with 4G infrastructure networks. Long-range wireless connectivity, cabling-free installation and multi-year lifetime are a unique combination of features, not available, to the best of our knowledge, in any commercial or research device. We discuss in detail the hardware architecture and power management of the node. Experimental tests demonstrate a lifetime of more than ten years with a 17000 mAh battery or completely energy-neutral operation with a small solar panel (60 mm x 120 mm). Further, we validate measurement accuracy and confirm the feasibility of modal analysis with the MEMS sensors: compared with a high-precision instrument based on a piezoelectric transducer, our sensor node achieves a maximum difference of 0.08% at a small fraction of the cost and power consumption.