Simultaneous Measurement of Strain and Temperature with two Resistive Strain Gauges made from Different Materials

Abstract

We present a novel approach for the differentiation between temperature and strain influence on resistive strain gauges. Two strain gauges are placed in a nested shape. The strain gauges are made from different materials. Due to the difference in strain sensitivity and thermal coefficient of resistance (TCR) of both materials, we can distinguish between resistance changes caused by temperature and by strain. Both strain gauges are exhibited to the same temperature and strain as they are placed very close to each other.In this work, we implement the concept on silicon substrates. The resistors are made from Platinum and Titanium which have a gauge factor of G.F.Pt = 5,933 and G.F.Ti = 0,0683 and a TCR of αT,Pt = 2.138*10-3 K-1 and αT,Ti = 1.733*10-3 K-1, respectively. The strain gauges are separately characterized for strain and temperature sensitivity. The concept is proved by measuring strain under the influence of an unknown temperature change.