About Preloaded FEMs

Preloaded FEMs copy the finite element model from an existing analysis case, step, and increment establish the starting point for a new simulation. The original (upstream) analysis cases used to create a preloaded FEM can include either explicit dynamic or static procedures. The new (downstream) simulations that use a preloaded FEM can include an explicit dynamic procedure or any implicit procedure type.

Note: Both the original and the new simulation must use MKS units. No units conversion is applied.

A preloaded FEM copies the following features from the results of the original simulation:

  • Mesh parts
  • Groups
  • Mesh numbering (if present)
  • Applied constraints (optional)
In the new simulation, you can delete the original groups and create new ones. You can remove mesh parts that you do not need, but you cannot modify meshes or mesh numbering.

When you create a preloaded FEM, it establishes a relationship between the original and new simulations. The original simulation generates the new FEM. A preloaded state feature in the new simulation identifies the step and increment from the original upstream analysis. If the original FEM changes, the preloaded state feature is used to update the preloaded FEM to match the changes from the original.

You can source and assemble multiple preloaded FEMs from different upstream simulations. If you generate preloaded FEMs from multiple simulations, each upstream simulation must use the same simulation procedure.

Typical Usage

You have a design and have completed simulations of its manufacturing processes. Now you want to simulate a drop test or other critical service or failure test.

Preloaded FEMs are typically used to simulate testing of parts or assemblies. The original simulation is generally an analysis of the manufacturing process, which might include casting, machining, heat treating, and assembly operations. These operations cause or relieve internal stresses and establish loading conditions on the component or assembly, which could impact the structural response during in-service life.

By generating a FEM from a selected step and increment of the results from the manufacturing simulations, the new FEM is preloaded with the stresses from those results. The preloaded FEM reflects the real state of the design. The preloaded FEM maintains a connection with the state of the original model, and you can define the new simulation with only the steps and conditions for the test. All the stresses from the original simulation are already included. Components can be reused in multiple simulations as-is, or they can serve as subcomponents in a larger model, which you can then use in various simulations.

 

See Also
Creating and Managing a Preloaded FEM