A Partitioned Frequency‐Domain Method for Nonlinear Dynamics Analysis of Large‐Deformable Structures Interacting With Finite‐Amplitude Acoustic Waves

Nonlinear structural‐acoustic interaction problems are conventionally solved by time marching methods, but they are computationally expensive for obtaining multi‐scale or bifurcation solutions, and are impossible to follow particular solution branches. This paper aims to develop a partitioned frequency‐domain finite element method (PFD‐FEM) to enhance the computational efficiency and versatility for nonlinear dynamics analysis of coupled large‐deformable structure and unbounded acoustic fluid systems. In the method, all variables of the structure and finite‐amplitude acoustic fluid are spatially discretized by nonlinear finite element method and temporally represented by the harmonic balance method. An arbitrary Lagrangian–Eulerian framework is adopted to update the acoustic meshes near the large‐deformable structural‐acoustic interface in the frequency domain. Several benchmark cases of nonlinear structural‐acoustic interaction, including finite‐amplitude acoustic waves radiated from large‐amplitude pulsating cylinder, pulsating sphere, vibrational beam, and vibrational plate, are used to validate the PFD‐FEM. Convergence studies are performed in these cases. Compared to time marching methods, nonlinear structural and acoustic responses as well as the contribution of different frequency components can be quickly and directly obtained by the proposed PFD‐FEM.