A 3D implicit structured multi-block grid finite volume method for computational structural dynamics

Abstract This work aims to develop a FVM-based structural solver that can seamlessly be integrated with Computational Fluid Dynamics (CFD) solvers for fluid-structure interaction (FSI) problems. For flexibility in gridding and efficient computation, hexahedral multi-block grids are adopted which are locally structured, but globally unstructured. Besides, ghost cells are introduced to solve the partial derivatives and displacements at the boundaries of the computational domain. Time-accurate solutions are obtained by employing a matrix-free, dual time stepping approach, and the implicit residual value smoothing method is used to increase the convergence rate. Stresses are evaluated using Green's theorem based on the gradients of the displacement of the cells. The proposed method is applied to static and dynamic response of 3D cantilevers. Results are found to agree well with analytical solutions, and the amplitude error of the dynamic response is less than 1.5%. Besides, resonance and beating phenomena were clearly observed and compared to Finite Element approaches in accuracy and efficiency. Finally, the dynamic response of a cantilever beam with NACA0012 airfoil is analyzed preliminarily.