Hierarchical model updating strategy of complex assembled structures with uncorrelated dynamic modes

In structural simulation and design, an accurate computational model directly determines the effectiveness of performance evaluation. To establish a high-fidelity dynamic model of a complex assembled structure, a Hierarchical Model Updating Strategy (HMUS) is developed for Finite Element (FE) model updating with regard to uncorrelated modes. The principle of HMUS is first elaborated by integrating hierarchical modeling concept, model updating technology with proper uncorrelated mode treatment, and parametric modeling. In the developed strategy, the correct correlated mode pairs amongst the uncorrelated modes are identified by an error minimization procedure. The proposed updating technique is validated by the dynamic FE model updating of a simple fixed–fixed beam. The proposed HMUS is then applied to the FE model updating of an aeroengine stator system (casings) to demonstrate its effectiveness. Our studies reveal that (A) parametric modeling technique is able to build an efficient equivalent model by simplifying complex structure in geometry while ensuring the consistency of mechanical characteristics; (B) the developed model updating technique efficiently processes the uncorrelated modes and precisely identifies correct Correlated Mode Pairs (CMPs) between FE model and experiment; (C) the proposed HMUS is accurate and efficient in the FE model updating of complex assembled structures such as aeroengine casings with large-scale model, complex geometry, high-nonlinearity and numerous parameters; (D) it is appropriate to update a complex structural FE model parameterized. The efforts of this study provide an efficient updating strategy for the dynamic model updating of complex assembled structures with experimental test data, which is promising to promote the precision and feasibility of simulation-based design optimization and performance evaluation of complex structures.