Preparation And Performance Study Of Thick-film Resistive Strain Gauge

This research aims to develop a new type of resistance strain gauge, which canbe applied to the local monitoring of structural health monitoring system. Strainsensors currently used for structural health monitoring, such as semiconductorstrain gauge, metal wire or foil strain gauge, piezoelectric sensors, optical sensors,shape memory alloys, etc, are subject to different limitations respectively in theapplication, such as high cost, poor sensitivity, difficulty of installation, complexityof data acquisition and processing, creeping, and poor reproducibility. Comparedwith the above-mentioned sensors, thick-film resistors（TFR） have high strainsensitivity, low temperature coefficient of resistance, low strain temperaturecoefficient, high stability, good repeatability, convenience of printing and sinteringprocess, low cost, which can indicate it’s applicantion to structural healthmonitoring as strain sensors. Based on that, the construction of TFR and the methodof testing TFR’s performance were studied, the method of modification of thick-film paste was explored, the conduction mechnism of thick-film was analyzed fromthe point of microstructure, the specific contents are as follows:（1） The preparation method of TFRs were explored. The TFRs were fabricatedby screen printing throngh appropriate sintering crafts and TFRs’ GF and TCR are9.619and44ppm/oC respectively.（2） The method of TFRs’ data acquisition and processing was studied. Theconnecting experiments between TFRs and static strainometer was carried out. Theresult showed that using static strainometer connected to TFRs by half bridge torealize data acquisition and processing is feasible.（3） The feasibility of using three kinds of modifiers （tungsten oxide, bariumtitanate and alumina） to change the thick-film paste was studied. The resultsshowed that effets of WO₃is better than other modifiers. The best doping ratio is20%, then the GF is18.967.（4） By means of scanning electron microscopy （SEM）, the structure of TFRswere analyzed from the microscopic point of view. And One-dimensionalconduction model was constrtucted. The effet of the ratio of conductive phaseparticle and the thickness of the barrier layer and the ratio of moduls of conductivephase and glass phase on the GF were studied.