Research on semiconductor strain gage balance technology applied in shock tunnel

The conventional strain balance or piezoelectric balance cannot meet the requirements of high precision aerodynamic measurement in the shock tunnel, as the effective test time is very short. The strain sensitivity of the semiconductor strain gage is much higher than that of the foil strain gage, but its temperature coefficient is two orders of magnitude greater than that of the foil strain gage. This paper designed a temperature-self-compensation semiconductor strain gage, and applied it on equal strength beam experiments. The results show that the temperature self-compensation technology can effectively improve the temperature effect of the semiconductor strain gage, and the temperature drift of the semiconductor strain gage is reduced down to 0.2% FS after temperature compensation. In this paper, a six-components balance with high frequency response is designed for the shock tunnel, and the results of calibration show that the combining loading repeatability and combining loading error of the balance meet the requirements of the national military standards. The balance can acquire more than one signal during effective test time as the inherent frequency of the test system is more than 100 Hz, and the results of the shock tunnel test are in good agreement with reference values of the aerodynamic manual and CFD results.