In-flight Loads evaluation by means of Strain measurements: a Numerical case study

This paper is concerned with one of the steps to be made for recovering of flight loads from strain measurements during flight: the ground calibration aimed at calculating the best Load evaluation matrices for the structural item to be considered. A methodology based on the Skopinski approach and aimed at selecting the best set and numbers of strain measurements on a two-spar wing has been set up. The work is of a numerical nature. It is intended to be a preliminary step before the real ground calibration to be made before flight. “Virtual” calibrations by means of extensive finite element calculations have been performed. The choice of the best set of strain sensors measurements and calibration loads has been made according to Skopinski approach. In particular two calibrations have been performed, the first with simple sets of loads, resulting in unacceptable results in terms of flight loads recovering (high percent errors). The second calibration has been carried out with sets of loads more similar to typical maneuvers or gusts encountered during flight, leading to quite reliable load evaluation matrices resulting in acceptable percent errors coherent with literature.