XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX''"> Group Averaging
In the General Setup Parameters on the main MSC Fatigue setup form you can select Group as the Nodal Averaging method. The default is Global and when set, element nodal results or results at gauss (integration) points are extrapolated to and averaged at the nodes from all element contributions. When this feature is set to Group, the averaging is done only for those elements in the current group. The following comments are made with respect to this feature:
1. This applies to nodal fatigue calculations only.
2. You must make sure you have the proper group set to be the current group. The current group is always displayed in the title of the graphics window. Use Group | Set Current... to set the current group.
3. Only one material and surface finish/treatment combination can be set with this feature.
4. This feature is convenient to use when you want to exclude the contributions of adjacent elements that may not be appropriate to include in the averaging such as when different materials or properties butt up against each other or you have some geometric features or element types.
As a simple explanation of this feature consider the four nodes to the right. For element nodal results, each of them has contributions from the surrounding elements shown as number in magenta (small font). These stresses are an indication of model quality. If they are all identical the element quality is perfect. This is rarely the case, however.
When Global averaging is set, all element contributions are considered in the averaging. Thus the stress values used will be as shown in blue (large font). If only the center element exists in the current group and Group averaging is set, the stress values at the nodes used in the analysis will be the contributions from the center element only. If the center element and the bottom three elements are in the current group then the averaged stresses will only contain the contribution from those elements as shown in green.
