A Technique for In-Situ Calibration of Semiconductor Strain Gauges Used in Hopkinson Bar Tests

Abstract

The semiconductor strain gauges (SCSGs) are widely introduced in Hopkinson bar technique to detect weak strain signals of low-impedance materials, just for its high gauge factor. But, the measurement accuracy is negatively affected by the instability of SCSGs’ specifications. A novel methodology is proposed to in-situ calibrate them and to interpret accurately the weak transmitted strain signals. And the dependence of the gauge resistance and factor on temperature and compressive/tensile loading conditions are calibrated with the stable electrical resistance strain gauges (ERSGs) as standard outputs. The results confirm that the properties present a high sensitivity to temperature, and even behave asymmetrically under tensile and compressive loadings. The experiments are carried out to verify the proposed in-situ calibration technique. Finally, the stress-strain curves of a shear thickening material are measured to demonstrate its reliability and detectability. This work will be useful to measure the dynamical mechanical properties of the soft and energy absorption materials like rubber and foams.