A new 8-node element for analysis of three-dimensional solids

We propose a new 8-node hexahedral element, the 3D-MITC8 element, for the analysis of three-dimensional solids. We use the MITC method and find the assumed strain field from a thought experiment using a truss idealization. For geometric nonlinear analysis, when needed to suppress hour-glass deformations, the formulation also uses automatically displacement-based contributions to the shear strains. The element shows a much better predictive capability than the displacement-based element. It is computationally more effective than the 8-node element with incompatible modes, and considering accuracy, in linear analysis performs almost as well, and in nonlinear analyses we do not observe spurious instabilities. We show that the new 3D solid element passes all basic tests (the isotropy, zero energy mode and patch tests) and present the finite element solutions of various benchmark problems to illustrate the solution accuracy reached with the new element.