Hysteresis Effects on Thrust Measurement and its Uncertainty

The work detailed herein describes a combination of experiments and numerical analysis meant to explore potential causes of both errors and hysteresis in a thrust measurement system and how they affect data reduction and uncertainty estimation. An uncertainty estimate of average hybrid motor thrust is also demonstrated. There were two major conclusions of this effort. First, hysteresis evident in a hybrid rocket motor test stand was eliminated through proper motor and thrust measurement system alignment. Second, Monte Carlo simulations showed that not including an elemental uncertainty contribution for hysteresis in an otherwise rigorous uncertainty propagation is a valid engineering approximation, when the experimental result is the average of data containing small (percentagewise) fluctuations. (Author)