Finite Element Model Tuning Using Analytical Sensitivity Values

Abstract

This paper presents an efficient approach for tuning finite element models to match the measured ground vibration test and proof test data. Frequencies, mode shapes, total weight, location of the center of gravity, and static deformation computed from the finite element model are matched to the measured data. The model tuning procedure used in this work is based on solving an optimization problem in which the errors for the considered metrics, between the finite element prediction and the measured data, are minimized. Analytical sensitivity values of performance indices are computed using the NASTRAN-generated sensitivity values together with the in-house computer programs, which allow for faster computational time and the use of gradient-based optimizers. The method is applied to the Aerostructures Test Wing 4 model. The study shows that the military standard and the NASA standard for comparing analytical and experimental modal data are all satisfied. The final finite element model correlates well with the test data. The flutter speed decreases by 8.91% after model tuning compared with the original Aerostructures Test Wing 4 design.