Measurement method by inferring the thrust from the stress of the cantilever beam based on the photoelasticity theory.

Abstract

A new, to the best of our knowledge, thrust measurement system based on the photoelasticity theory has been developed to infer the thrust from the stress of the cantilever beam. In this method, the cantilever beam is employed as the loading element to convert the low thrust into high stress, and the modified dynamic photoelasticity is used to infer the stress value of the cantilever beam from the Stokes parameters of the emergent light. The experimental results validated that the thrust stand could measure the thrust in the range of millinewton or millisecond, and the thickness of the beam was negatively correlated with the measurement accuracy. The average errors of the experimental measurements for ampere forces were higher than 25 mN and the pulse ampere forces whose widths were longer than 45 ms were less than ${\pm 5}\% .$±5%. As for the real plasma discharges, the errors of the measured thrust were less than ${\pm 10}\% $±10%.