Relevant engineering software: MSC Nastran
Challenge: To further analysis of finite element models, there are times when a mesh must be refined or modified in some way. Refining a mesh requires a large amount of time:
- Defining mesh transitions
- Aligning nodes so they are coincident
- Splitting elements
- Creating separate and detailed analysis models
|Note the mesh transitions and congruent meshes.|
Alternative: Use finite element modeling technology known as permanent glued contact that reduces the need to align incongruent nodes. In effect, you can join dissimilar meshes and perform an analysis without having to go through an exhaustive remeshing process.
|Note the attachment of incongruent meshes.|
|The results remain continuous across meshes.|
What are some examples of Permanent Glued Contact?
There is solid face-to-face.
|In this case, Tet elements are attached to an incongruent Hex mesh.|
There is shell edge-to-face. The edges of shell elements are attached to the faces of other elements such as solids or shells.
|Shell edges are attached to the faces of other shell elements.|
|In this example, you have two types: shell edge to solid face and shell edge to shell face.|
You can have shell face-to-face, i.e. the shell faces are attached to one another.
You can also have edge-to-edge permanent gluing, where the edges of shells are attached.
What is integrated Global Local Analysis?
“The whole system is first analyzed as a global entity, discarding or passing over details deemed not to affect its overall behavior. Local details are then analyzed using the results of the global analysis as boundary conditions. The process can be continued into the analysis of further details of local models. And so on. When this procedure is restricted to two stages and applied in the context of finite element analysis, it is called global-local analysis in the FEM literature.” 10 Superelements and Global-Local Analysis p. 9
Basically, your finite element model can begin very coarse, only taking into account critical structural features. As you progress in your analysis, you add a finer mesh to represent additional features that were previously left out.
With permanent glued contact, performing Global-Local analysis is simpler since the trouble of meshing is greatly reduced.
In MSC Nastran, what analysis solutions support permanent glued contact?
- Linear Statics
- Normal Modes
- Direct Complex Eigenvalue
- Direct Frequency Response
- Direct Transient Response
- Modal Complex Eigenvalue
- Modal Frequency Resposne
- Modal Transient Response
- Implicit Nonlinear Static and Dynamics
- Design Sensitivity and Optimization
Where can I learn more?
You can watch this 5 minute video detailing Glued Contact in MSC Nastran.
Need even more information?
You can watch this 45 minute presentation.Or you can watch our SimAcademy webinar detailing how to take advantage of Glued Contact in MSC Nastran.