An Efficient Re-Analysis Methodology for Vibration of Large-Scale Structures

Finite element analysis is a well-established methodology in structural dynamics. However, optimization and/or probabilistic studies can be prohibitively expensive because they require repeated FE analyses of large models. Various reanalysis methods have been proposed in order to calculate efficiently the dynamic response of a structure after a baseline design has been modified, without recalculating the new response. The parametric reduced-order modeling (PROM) and the combined approximation (CA) methods are two re-analysis methods, which can handle large model parameter changes in a relatively efficient manner. Although both methods are promising by themselves, they can not handle large FE models with large numbers of DOF (e.g. 100,000) with a large number of design parameters (e.g. 50), which are common in practice. In this paper, the advantages and disadvantages of the PROM and CA methods are first discussed in detail. Subsequently, a new re-analysis method is proposed where the original CA method is modified to further improve its efficiency, especially for problems where a large number of modes is required. The modified CA (MCA) method is then integrated with the PROM approach, in order to formulate an efficient new reanalysis method that is suitable for large FE models with many design parameters that vary in a wide range. A simple frame structure is used to explain all steps of the proposed method. Also, a vibro-acoustic analysis of a realistic vehicle FE model is presented to demonstrate the efficiency and accuracy of the new method. A design optimization study is also performed to highlight the accuracy and efficiency of the proposed re-analysis method.