Thick Resistive Film Application on Steel Bars for Structural Health Monitoring

This paper aims to examine the applicability of thick-film piezo-resistive sensors on steel bars for the structural health monitoring purposes. A thick film ceramic piezo-resistive sensor was manufactured and used to investigate the possibility of its application on a bar. To form the device, Bi
2
Ru
2
O
7
resistive thick-film composition was used in combination with Pd/Ag conductive composition on alumina ceramic substrates. Six conductive pads divided the resistor into seven identical segments. Sensor was subjected to a three-point bending test. After it was glued to a steel bar like a common foil strain gauge, a four-point bending test was performed on a sensor placed on the upper side of the bar. Under strain, sensor experienced reversible deformation that was registered as a change in the resistivity of the film. Evaluation of the sensor included measurements of the resistance change under the applied strain, determination of the gage factor and investigations of its physical integrity and temperature stability.