Modeling Fabricated Structures
Reducing weight while improving structural performance and design aesthetics is a challenge every engineer faces. Sheet metal is a common “traditional” material used in many industries to minimize material and weight while delivering required performance. Structures made of slender plates are largely used in industrial equipment (casings, crane, etc.) as well as in transportation applications, like trains or ships.
These slender plates involve a different set of challenges for meshing than 3D structures. An efficient workflow is required to manage a large number of bodies in an assembly and allow the user to create a meshed model in an automated way.
The video below demonstrates the typical workflow for such structures and demonstrates the efficiency of the process. You can automatically create a simulation model from a complex assembly in minutes.
with ANSYS Mechanical
Here is what a typical workflow looks like using ANSYS tools:
- Prepare the geometry, extracting midsurface or top/bottom surface
- Imprint geometry where needed, especially at T-junction
- Add welds to join parts (optional)
- Mesh all parts of the model Individually, leveraging parallel meshing for high performance
- Connect parts after the initial individual meshes have been created
- Check quality and manually edit the mesh if needed
- Apply loads and boundary conditions
- Solve the model
- Review the results
- Perform automated design variations by modifying geometry dimensions, physical properties or loads or boundary conditions
The process starts with preparing the geometric model for the simulation. This includes midsurfacing as well as imprinting faces that are touching.
Once the meshes of individual faces have been generated, the model can be connected so as to have coincident nodes at intersections of faces. Note that contact or other types of connections could be used, depending on how the model should behave.
Element quality can then be easily checked on the model. If needed, you can move nodes of the mesh to locally improve quality.
As all operations above can be automated, it is then easy to perform design variations on the model using the parametric capabilities of ANSYS Workbench.
As fabricated structures can be very large – think for example of an offshore platform — you may also want to work on sub-assemblies for a more efficient setup. You then need to assemble all the various parts to create a model of the full structure and connect them just like you would do for various sheet metal parts.