Generalised plane strain elements

 

Each generalised plane strain element has three, four, six or eight conventional nodes and two extra nodes. Generalised plane strain elements (CGPE*) are therefore represented by FEMGEN element types: TR3, QU4, TR6 and QU8 (see tables 2.2 and 2.3). The two additional nodes are determined as follows:

• By default, all the CGPE* elements in the model will have the same two extra nodes. Both nodes will have the same coordinates as the origin (0,0,0).
• The user can specify the location of the two extra nodes by giving the following special names to FEMGEN points: 'GPSX1***' and 'GPSX2***' (where * can be any printable character). Note that if only one of the two nodes is defined by a point, the other node will have the coordinates of the origin. Here again, the two extra nodes will be the same for all the CGPE* elements in the model.
• If the CGPE* elements are not all using the same pair of extra nodes, then the user can create sets called 'GPS*****' to group together the CGPE* elements that are going to use the same extra nodes. There will be a pair of extra nodes for each set, (by default they will have the coordinates of the origin) alternatively if points with a name starting by 'GPSX' are included into the set, these define the extra nodes.
• If boundary conditions exist at any of the extra nodes, it is necessary to define them by creating 'GPSX****' points, so that the boundary conditions can be applied in FEMGEN at these geometric points.