How to Use CFD Results as FEA Inputs for Multiphysics Analysis 

For many real-world scenarios, multiphysics simulation is essential to achieve accurate results.  

Multiphysics refers to the analysis of multiple interacting physics domains and is critical whenever one physics domain influences another.  

Two of the most common combinations are: 

1. Fluid-Structure Interaction (FSI): Combining fluid flow and structural stress analysis. 

1. Thermal-Structural: Combining thermal and structural stress analysis.  

In this blog article, we’ll take a look at how to set up these two types of multiphysics simulations by using computational fluid dynamics (CFD) results as finite element analysis (FEA) inputs. 

We will explore the workflow to do this in both the desktop simulation tools from SOLIDWORKS — Flow Simulation and Simulation — and the cloud-based 3DEXPERIENCE SIMULIA tools. 

If you’re the kind of person who prefers watching a video over reading, we discussed an FSI example and more details on multiphysics simulation in 3DEXPERIENCE SIMULIA at our annual Design to Manufacturing (D2M) Virtual Conference. 

Workflow 1: Using CFD Results as FEA Inputs with SOLIDWORKS Flow Simulation and SOLIDWORKS Simulation

First, let’s discuss how to set up and use CFD results as FEA inputs using SOLIDWORKS Flow Simulation and SOLIDWORKS Simulation. 

CFD Setup in SOLIDWORKS Flow Simulation

For both FSI and thermal-structural cases, the first thing you need to do is create a CFD study in SOLIDWORKS Flow Simulation.  

Our Goals 

• For an FSI analysis, the goal is to determine the forces the fluid flow exerts on the surfaces of the solid bodies.  
• For a thermal-structural analysis, the goal is to determine the temperature of the solid bodies. 

The setup for these studies is no different from any other typical CFD setup in Flow Simulation. The only additional step needed, specifically for FSI, is to go to Tools, Flow Simulation, Tools and click Export Results to Simulation as shown in the image below. This is not necessary for thermal-structural. 

FEA Setup in SOLIDWORKS Simulation

Next, you need to create an FEA study in SOLIDWORKS Simulation. You’ll want to define your simulation details (materials, connections, fixtures, mesh, and so on) as usual.  

What’s special here is how you’ll bring in your loading.  

If you right-click on External Loads, you’ll see options for Flow Effects and Thermal Effects, which both send you to the Flow/Thermal Effects tab of the study properties. 

Setting Up FSI 

For FSI, check the box to “Include fluid pressure effects from SOLIDWORKS Flow Simulation” and browse to the results file for the CFD study you created earlier. If this is the only Flow Simulation project for the file, you should find “1.fld” in a folder named “1”.  

Click OK and you’ll see Fluid Pressure and Fluid Shear Stress loads listed under External Loads. 

Setting Up Thermal-Structural 

For thermal-structural, choose the thermal option Temperature from SOLIDWORKS Flow Simulation and browse to the results file for the CFD study you created earlier in this first workflow.  

Double-check the zero-strain reference temperature is appropriate, click OK, and you’ll see a Thermal load listed under External Loads. 

Workflow 2: Using CFD Results as FEA Inputs with 3DEXPERIENCE SIMULIA 

Now, let’s discuss how to set up and use CFD results as FEA inputs using 3DEXPERIENCE SIMULIA.  

CFD Setup in 3DEXPERIENCE SIMULIA

For both FSI and thermal-structural cases, the first thing you need to do is create a CFD study using the Fluid Model Creation and Fluid Scenario Creation apps.  

Our Goals 

• For an FSI analysis, the goal is to determine the forces the fluid flow exerts on the surfaces of the solid bodies.  
• For a thermal-structural analysis, the goal is to determine the temperature of the solid bodies.  

The setup for these studies is no different from any other typical CFD setup with the Fluid Dynamics Engineer role.  

The only additional step needed, specifically for FSI, is to define a Port Region, which you’ll find on the Contacts tab of the Action Bar. You’ll need to select the faces where the fluid forces will be transferred to the FEA simulation. This is not necessary for thermal-structural. 

FEA Setup in 3DEXPERIENCE SIMULIA

Next, you need to create an FEA study using the Structural Model Creation and Mechanical Scenario Creation apps. You’ll want to define your simulation details (materials, connections, fixtures, mesh, and so on) as usual.  

What’s special here is how you’ll link your pressure or temperature to the CFD simulation. 

Setting Up FSI 

For FSI, you’ll need to define a Port Region to match the Port Region defined in the fluid scenario. You’ll find Port Region on the Interactions tab of the Action Bar. Again, you’ll need to select the faces where the fluid forces will be transferred.