Finite element model of a large spacecraft structure updated with modal test

Abstract

AHSTRACT This paper presents a new technique to improve the error location phase previous to the updating process of finite element models using modal test data, Mass and stiffness error matrices of the model are calculated applying the error vector technique. Modal assurance criteria (MAC), Normalised cross orthogonality (NCO) and SEPEP theoretical mass reduced based normalised cross orthogonality (SCO) correlation coefficients are considered. The analytical model of the structure is updated on the basis of experimental data using a direct updating method, and new stiffness and mass matrices are generated. The error matrices of the model are analysed in order to identify the major modelling error regions. Errors are assigned to the different elements of the model and plotted with colour range on the mesh. The process of error interpretation is simplified and physical meaning can be deduced. These updating methods have been applied to the analytical model updating of the Polar Platform Panel.