Abstract：For aerospace hierarchical structures, accurate finite element models are crucial. They help predict structural response, monitor health status, and identify loads. However, the modeling process is always accompanied by simplifications, including structural idealization, material approximations, and neglect of manufacturing errors. Therefore, model predictions often deviate from actual dynamic behavior, making it difficult to accurately capture true mechanical properties under complex operating conditions. To address this issue, this paper proposes a novel modeling and updating method. This method comprises two key parts. First, a hybrid finite element model is constructed using shell and solid elements. Preloading is applied via a cooling method to ensure computational efficiency and numerical stability. Simultaneously, explicit rules are defined for shell dimensions and offset directions, which help maintain the geometric accuracy of contact definitions and ensure the correct transfer of mechanical behavior between elements. Second, a "building block" dynamic model updating strategy is developed. The aerospace structure is divided into three layers: parts, components, and assemblies. Modal testing is performed progressively at each layer. Subsequently, a hybrid optimization method is employed. This method combines a multi-island genetic algorithm with a sequential quadratic programming algorithm. The genetic algorithm handles the global search, while the quadratic programming is used to optimize local solutions. This combination enables efficient and accurate layer-by-layer updating of model parameters. The results show that this method transfers update effects from lower to higher levels and fixes them in place, thus significantly improving model fidelity. This paper provides a systematic solution for high-precision dynamic modeling of layered structures in aerospace applications. The method integrates preload effects, ensures geometric accuracy at hybrid element contacts, and enables experiment-guided layered model updates. It significantly narrows the gap between numerical predictions and actual dynamic responses. This method provides a robust approach to building high-fidelity dynamic models under complex loading conditions and has significant value for the design, analysis, and maintenance of complex aerospace structures.
2026, Vol. 47 
