Generally, identical bilinear approach functions with 2, 3, or 4 boundary nodes are to be used, depending on which element you prefer, but there are differences in the quadrature. The differences in the quadrature are as follows:
Elastic calculation:
Truss member: analytically 2 nodes 3 degrees of freedom
Beam: analytically 2 nodes 6 degrees of freedom
Surface (plate): analytically (LYNN-DHILLON-Element)
Surface (wall): Quadrangular Gauss quadrature 2x2, triangular selective quadrature (epsilon_x; epsilon_y; gamma_xy)
Solid: Gauss quadrature 2x2
Nonlinear calculation (for example, plasticity, and so on):
Beam:
2-point Gauss quadrature in the longitudinal direction of the member
across the cross-section Gauss quadrature 2x2
Surface (plate):
in the element surface: quadrangular Gauss quadrature 2x2 , triangular 3-point Gauss quadrature
per thickness 9-point Gauss-Lobatto quadrature
Wall - quadrangular Gauss quadrature 2x2, triangular 3-point Gauss quadrature
Solid - 14-point reduced Gauss quadrature (equivalent to the 3x3x3 Gaus quadrature)
![Spans Based on Figure 5.2 from [1]](/en/webimage/039540/3493372/01_Abmessungen_EN.png?mw=512&hash=3cc425f1463bd5981b358d5889e3109e07ae1233)
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