Alternate representation (component FEM file)

An alternate component representation can represent structural or vibro-acoustic simulation results, or it can be derived from vibration test data. The alternate component representation is a computationally reduced form of the original component structural or vibro-acoustic behavior. Solving assembly FEM models, or standalone models, with computationally reduced components can reduce your model complexity and required solution resources.

Example of an assembly FEM with alternate representations connected with elastic connectors (1) FEM component; (2) Mode Set; (3) FRF Set; (4) Superelement; (5) Simcenter Testlab data

For example, you can create a hybrid assembly FEM, such as an assembly for an automotive NVH analysis, that contains both complete FEM component models and reduced FEM components (also called alternate representations). You can use a reduced component FEM to represent the automotive body-in-white, but use a complete FEM of a suspension cross member.

You can use the following data sources for alternate representations:

• For Mode Sets and FRF Sets, the data source can be .op2, .unv, and Simcenter Testlab files.

• For superelements, Acoustic Transfer Vector (ATV) Sets, and Vibro-acoustic Transfer Vector (VATV) Sets, the data source is an .op2 file.

• For DMIG representations the data source is a .fem file, which was created from a SOL 103 Superelement solution. For more information see DMIG as a matrix element

Note:

If the Simulation file is the work part, you can select the .op2 results from the Simulation Navigator.

The general workflow for using alternate component representations in an assembly FEM is as follows:

1. In the Simulation Navigator, assign a superelement, Mode Set, FRF Set, or ATV to represent a component FEM, or VATV Set to represent a FEM or assembly FEM.For more information on superelement, Mode Set, or FRF Set use, see Replace a FEM file with a mode set or FRF set.For more information on ATV or VATV Set use, see Replace different FEM files with an ATV set or VATV set.

2. Connect the alternate representation to other component FEMs using elastic connectors, such as springs or beams. Note: Rigid elements (RBE2, RBE3, or MPC) are not valid in these connections.For more information, see Connecting component FEMs.

3. In the associated Simulation file, create a solution.

4. Apply boundary conditions (except for VATV response solution), loads, and output requests, and then solve the solution.Note: The VATV matrix already contains boundary conditions and constraints.

5. Evaluate the results.

Learn more

Alternate representation (standalone FEM file)

Visualization elements (PLOTELs) in assembly FEM files

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Assembly FEM

Alternate representation (component FEM file), Simcenter 3D 2021.1 Series

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