Shell element – shell4

This element is a 3D Shell element with 4 nodes (quadrilateral shell element). It follows the mixed-interpolated tensorial components (MITC) element formulation as described by Dvorkin and Bathe (1984). The element combines plate-bending and membrane behaviour. The shell element can be used for the modelling of structural elements like floors/plates (applicable both for thin and thick plates) and walls and in general surfaces carrying in-plane and out-of-plane loading. The element is elastic with six degrees of freedom per node.

In this element's dialog box it is also possible to define an element-specific damping, as opposed to the global damping described in here. To do so, users need simply to press the Damping button and then select the type of damping that better suits the element in question (users should refer to the Damping menu for a discussion on the different types of damping available and hints on which might the better options). Users are reminded also that damping defined at element level takes precedence over global damping, that is, the "globally-computed" damping matrix coefficients that are associated to the degrees-of-freedom of a given element will be replaced by coefficients that will have been calculated through the multiplication of the mass matrix of the element by a mass-proportional parameter, or through the multiplication of the element stiffness matrix by a stiffness-proportional parameter, or through the calculation of an element damping Rayleigh matrix.

Note: If Rayleigh damping is defined at element level, using varied coefficients from one element to the other, or with respect to those employed in the global damping settings, then non-classical Rayleigh damping is being modelled, classing Rayleigh damping requires uniform damping definition.

Local Axes and Output Notation