Membrane Elements (esas.37)



This module offers possibility to use membrane elements in the modelling and calculation. Membrane elements are defined as shell elements which have no flexural stiffness and no axial compression stiffness. Membrane elements can thus be used to model canvas, nets, etc. that are subjected to axial tension.

To obtain realistic results, a 2nd order calculation needs to be executed using the Newton-Raphson method.

Calculation of shells as 2D-elements with tensile axial stiffness only.

The deformed mesh for the non-linear analysis shows that the canvas has been pulled straight.

Differences in the results between membrane and standard element

The difference in the obtained results resulting from the application of the membrane behaviour can be best demonstrated on a simple example. Let us assume a rectangular plate made of a very thin sheet of steel. The left-hand side of the figure shows the results obtained for a standard 2D element. The right-hand side then contains the results for the membrane elements.

Note: Membrane elements can only be modelled in a General XYZ environment. Due to the fact the flexural rigidity is zero, no ribs, no prestressed tendons, orthotropic parameters or physical non-linear data can be inputted on a membrane element. Since a membrane element has no axial compression stiffness, no concrete calculation nor CDD can be performed on this type of element.