The default integration method for surfaces in RFEM is the Gauss-Lobatto quadrature with nine integration points. This default setting is sufficient for most cases.
In order to accurately model nonlinear stress-strain distributions, it may be useful to increase the number of integration points.
Therefore, when using nonlinear material, it is possible to define the number of integration points in each layer between three and 99 user-defined points.
However, please note that a higher number of integration points results in a longer calculation time.
The following three different integration methods can be selected.
- Gauss-Lobatto quadrature
- Simpson's rule
- Trapezoidal rule
A more detailed description of the integration methods can be found in the manual for multi-layer surfaces in the following linked chapter Theory of Integration Methods.
The integration method can be defined in the thickness of the surface. The following image shows the corresponding input dialog box.
The technical article Influence of Various Integration Methods on Calculation of Steel Fiber-Reinforced Concrete Slab provides an overview of the methods using an example.