Continuum mechanics-based shell elements with six degrees of freedom at each node − the MITC4 / D and MITC4+ / D elements

We give the formulation and numerical assessment for using six degrees of freedom at each node of 4-node continuum mechanics-based quadrilateral shell elements. The formerly published MITC4 and MITC4 + shell elements are considered and extended to now include the drilling rotational degrees of freedom at the nodes. Including these degrees of freedom enables the modeling of shells with beam elements and shell surfaces intersecting at large angles and in addition results in an improvement of the membrane behavior of the elements. The elements pass all basic tests, show alleviated locking behavior in the analysis of general curved geometries and show close to optimal convergence behaviors in the analysis of the “all-encompassing” shell test problems.