An experimental analysis of accuracy and precision of a high-speed strain-gage system based on the direct-resistance method

An experimental study about the relative merits of using a high-speed digital-acquisition system to measure directly the strain-gage resistance rather than using a conventional Wheatstone bridge, is carried out. Both strain gages, with a nominal resistance of 120 Ω and 1 kΩ, are simulated with precision resistors and the output signals were acquired over a time of 48 and 144 hours; furthermore, the effects in metrological performances caused by a statistical filtering are evaluated. The results show that the implementation of the statistical filtering gains a considerable improvement in gathering straingage-resistance readings. On the other hand such a procedure causes, obviously, a loss of performance with regard to the acquisition rate, therefore to the dynamic data-collecting capabilities. In any case the intrinsic resolution of the 12-bit a/d converter, utilized in the present experimental analysis, causes a limitation for measurement accuracy in the range of hundreds μ m/m. Paper was originally presented at the 1991 SEM Spring Conference on Experimental Mechanics held in Milwaukee, WI on June 9–13.