A hybrid reduced-order modeling technique for nonlinear structural dynamic simulation

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Thin-walled structures are always subjected to a large range of extreme loading cases leading to obvious geometric nonlinearities in structural dynamic response, such as vibration with large amplitudes in aeronautics and astronautics field. Various dynamic reduced-order models have been investigated from detailed finite element models, to largely reduce the computational burden of the structural dynamic responses. However, to construct these low-order models, applying a series of nonlinear static simulations to the full-order model is necessary. This paper aims to develop a hybrid reduced-order modeling method by combining the dynamic and static reduced-order models together, to estimate the dynamic transient response caused by geometrically nonlinear finite element models. A few free-vibration modes of interest are selected to reduce basis vectors of dynamic reduced-order model. Based on Koiter asymptotic expansion theory, the constructed static reduced-order model is applied to the nonlinear static analyses. Therefore, not only does the proposed method make it possible to calculate the nonlinear dynamic response far more efficiently than full-order modeling methods, but computational burdens in construction of dynamic reduced-order model are also largely reduced compared to existing approaches. Various engineering numerical examples with hardening and/or softening nonlinearities are carefully tested to validate the good quality and efficiency of the proposed method.