Investigation on the Influence of Temperature Variation on the Response of Miniaturised Piezoresistive Sensors

This paper deals with the analysis of temperature response of miniaturised piezoresistive strain sensors. Amorphous silicon sensors of different geometry were deposited on a glass specimen: on the basis of previous studies, each sensor has a linear response and can be compared with a full Wheatstone bridge, but dimensions and power consumption are much lower than those of ordinary resistance strain gauges. A preliminary experiment was performed to prove the robustness of sensor response, considering connections to the acquisition device having different lengths. The main experimental campaign was aimed at investigating the influence on response because of temperature variation during each test. Eight different sensor configurations were tested, both under load and no-load conditions, with three replications. This paper describes test installation and measuring chain for simultaneous acquisition of both temperature and sensor voltage output. Thermal response linearity and hysteresis effects were investigated. In addition, the results, whose repeatability over the three replications was checked, made it possible to determine and compare the sensitivities of each sensor configuration to temperature variations. Analysis of variance (ANOVA) showed that, despite its different values for configurations with different geometry, sensitivity remains the same under load or no-load conditions.