Hypersonic Aerodynamic Force Balance Using Temperature Compensated Semiconductor Strain Gauges

Abstract

Metal foil strain gauges remain the state-of-the-art transducers for wind tunnel balance. While strain gauge technology is very mature, piezoresistive semiconductor sensors offer alternatives that are worth exploring to assess the unique benefits, such as better strain resolution and accuracy, which would enable balances to be designed with higher factors to safety and hence longer fatigue lifetimes without sacrificing force resolution and accuracy. A new three-component balance, based on temperature compensated semiconductor strain gauges, has been designed, calibrated and tested in a hypersonic low density wind tunnel. The static accuracy of the semiconductor balance is calibrated better than 0.3%, and the dynamic accuracy of the balance is established using a HB-2 standard model in Mach 12 hypersonic flow. Good experimental repeatability was confirmed to be better than 2.5%, and the effectiveness of the balance is demonstrated by comparing the forces and moments of measured data with computational fluid dynamics simulations, as well as reference wind tunnel results under similar condition.