An unsymmetric 8-node hexahedral solid-shell element with high distortion tolerance: Linear formulations

A locking-free unsymmetric 8-node solid-shell element with high distortion tolerance is proposed for general shell analysis, which is equipped with translational degrees of freedom only. The prototype of this new model is a recent solid element US-ATFH8 developed by combining the unsymmetric finite element method and the analytical solutions in three-dimensional local oblique coordinates. By introducing proper shell assumptions and assumed natural strain modifications for transverse strains, the new solid-shell element US-ATFHS8 is successfully formulated. This element is able to give highly accurate predictions for shells with different geometric features and loading conditions and is quite insensitive to mesh distortions. In particular, the excellent performance of US-ATFH8 under membrane load is well inherited, which is an outstanding advantage over other shell elements.