An Low-Power Embedded System for Long Term Measurements of Compressive Stresses in Solids

Structural damage due to high traffic loads is becoming an increasing problem for infrastructure buildings such as bridges. Continuous measurement of structural parameters over long periods of time is providing valuable information for observing structural health and tracking the progress of already known damages. Therefore, new measurement methodology towards autonomous and long-term measurement requires cheap, reliable and energy efficient sensor platforms. This issue is addressed for compression stress measurement by the proposed sensor device, which is comprised of an ultrasonic stress sensor based on the acoustoelastic effect, combined with an embedded measurement system optimized for low energy requirement at 12.66 mWs per measurement. Interfaces for wired communication and power supply or wireless near field communication (NFC) data exchange and energy harvesting are integrated. The system provides a robust solution for application in the field of structural health monitoring and has been tested on an experimental basis for measurement range, accuracy and power consumption.