FEA Simulation Tutorial using ANSYS

FEA simulations involve the numerical solving of partial differential equations that rule our known world. The simulation software takes in a geometry and then creates a mesh out of it. A mesh is your geometry broken into a large, but finite number of elements. Each of these elements, whether they be cubes, tetrahedrons, pyramids, etc. can then have a PDE applied over it. The specific PDE applied depends on the type of simulation you are running. For instance, for an electric simulation Maxwell’s equations will be applied, and for thermal simulations the heat equation will be applied. Once your geometry is separated into a number of finite elements, you can then apply boundary conditions to the entire geometry. These boundary conditions include but are not limited to an applied force, an applied pressure, heat applied, and a voltage. The software then takes the boundary conditions coupled with your mesh and continuity equations in order to produce the results you are asking for. These results could be deformation, stress, strain, resultant force, etc. The main softwares you will use to complete simulations are FEA within Solidworks, ANSYS’ FEA simulations, COMSOL, and/or simscale. We highly recommend ANSYS as it is highly accurate and we have access to free licenses.

To begin using Ansys, open the Workbench application. Select the static structural icon on the left menu to begin working on a static structural project. The project window will contain several items that you must fulfill in order to run the simulation.

• Engineering Data

  • The Engineering Data item is where you select the material that the component is made out of. You can choose from an extensive list of preloaded materials that Ansys offers, or you can create your own material with its own properties. This might be helpful for asymmetric materials or extremely unique materials, but we will generally be able to get good results from preloaded materials.

• Geometry

  • The Geometry item is where you will be importing or creating the 3D part you will be running the analysis on. While it is possible to create the part in Ansys, we strongly recommend using SolidWorks or some other 3D modeling software to create and save the part, and then import that part into Ansys. To do this, simply select Import Geometry, and Browse to look for the file.

• Model

  • Selecting Model will bring you to a new window (after a significant loading period) where you will be completing the rest of the items. Here, you will be assigning the material to the body, creating the mesh, and specifying the conditions and settings of the FEA.

    • To assign a material, click on Materials in the directory on the left of the window, and insert your material with Material Assignment. Then, select the whole body, reselect Material Assignment, and click apply

      • You can select different things on the body, like surfaces, vertexes, etc. using the boxes above the model window

    • Now we must create the mesh. This is creating the finite elements in the finite element analysis. To start, you can simply click on the Mesh tab and generate mesh to see what Ansys will give you. Usually, we want a more fine mesh for more accurate results. To do that, select mesh, go to insert, and select sizing. From there, you will select the geometry just as you did for material assignment. You will now be able to customize the mesh size once you select generate mesh! A word of caution, too fine of a mesh will cause very long loading times, so don’t go crazy.

    • Next, we must assign boundary conditions. To do this, go into Static Structural, go into Insert, and you will be given a long list of different boundary conditions to use. We went simple with just a force and a fixed support, but you are certainly welcome to play around with some of them to see how they actually operate. Just select the faces and/or lines that you want these conditions to be applied to using the geometry selecting tools above the model. Again, be careful, because too many tasks for the program to control will lead to very large loading times.

    • To actually get the results of the simulation we plan to run, we must enter the solutions we want the program to solve for. To do this, select Solution, select Insert, and you will be given a list of the different solutions that you would like the program to solve for. Make sure to apply the solution type to the geometry otherwise you will get no results. From there, if you have completed all of these steps correctly, you are ready to select Solve!

    • To understand the results, go into your solution on the left hand menu, once it has finished solving. Here you will be able to see contours of the questions you asked the software to solve. For instance, if you are running a static structural analysis, you should have asked the software to tell you deformation. Feel free to click through each of your asked solutions. While doing this go through mental checks to make sure that what the computer has solved fits what should have happened. Does the part deform the right way? Does the temperature distribution look right? If the answer to any of your mental checks doesn’t fit what should have happened then go back through your setup to ensure everything is correct. ANSYS does a great job of solving what you give it, but it doesn’t know what is “supposed” to happen; it just solves from what you enter.

Once you have gone through your mental checks and confirmed that it is following expectations, feel free to tentatively trust the results. To stress again, while ANSYS is great at simulating, at the end of the day, all it does is simulate what would happen as accurately as it can. Always use simulating in conjunction with hand calculations, scale model tests, etc.