ABSTRACT A finite element model of a structure can be updated as certain criteria based on experimental data are satisfied. The updated FE model is considered a better model for future studies in dynamic response prediction, structural modification, and damage identification. A finite element model updating technique incorporating the concept of response surface approximation (RSA) requires no sensitivity calculations and is much easier to implement with a general-purpose finite element code. The proposed updating method was incorporated with MSC.Nastran to solve the updating problem for an H-shaped frame structure. The updated results show that the predicted and experimental modes are correlated well with high MAC values and with a maximum frequency difference of 1.5%. Moreover, the updated parameters provide a physical insight to the modeling of bolted and welded joints of the H-frame structure. INTRODUCTION Finite element model updating [1] is a study in how to combine the strength of both the finite element (analytical) and experimental analyses for studying the dynamic behavior of a structure. Although the finite element (FE) method produces more natural frequencies, mode shapes, and spatial information to characterize the structure, the accuracy of these results usually requires further experimental confirmation. The experimental modal testing, on the other hand, yields fewer modes and less spatial resolution, but generally inspires more confidence in its results. A finite element model of a structure can be updated as certain criteria based on experimental data are satisfied. The updated FE model is considered a better model for future studies in dynamic response prediction, structural modification, and damage identification. In the early years of the development of finite element model updating, most authors studied cases for simulated structures only. In recent years, more and more model updating cases for real structures have been reported, e.g.
