Occupant Cell Simulations Setup and Meshing

Preparing Geometry in SolidWorks

It is first important to ensure that after you have created a frame model with weldments, there are no interferences present. This will cause issues with the simulation
We will then create the locations for the loading patches using the competition-sepcified locations and sizes.

Use the interference tool to solve for any interferenes and use the trim tool accordingly

Create a reference plane some arbitrary distance from the front of the car

Draw a sketch of the rectangle on the plane that will serve as the loading patch for the front impact test. Use the dimensions and height above the ground given in the regulations.

Repeat steps 2 and 3 for the rear

Create a reference plane for the side impact loading patches
Create the loading patch rectangle the same as the previous steps, but don’t define the longitudinal distance. We will define these later

Open a 3D sketch, and create points at the centers and corners of each of the center rectangles you have just created

Ctrl+c and ctrl+v the 3D sketch from the feature manager tree into a new part, and save as a .IGES file into a folder you can access for later

Finally, save the part as a Parasolid File and go to ANSYS Spaceclaim

Preparing Geometry in ANSYS Spaceclaim

We’re going to use Spaceclaim to extract our tube space frame into beam elements.
Beam elements are 2 node elements that more simply model long and slender structures, such as tubes. They can model problems with bending, torsion, axial forces, and large deformations.
We opt to use beam elements because of their quick solver time, as well as their ability to quickly make iterations by simply adjusting the cross-section of the beam element.

Create a new ANSYS workflow, and import the new Parasolid geometry you created

Navigate to the Prepare tab and select “Extract”. Then box select the whole frame

Select Connect, then set the maximum distance to 5 mm and click the check mark until the red dots disappear. Slowly increment the maximum distance up until all of your gaps are gone/you have clean intersections between beam elements

Expand the Beam Profiles folder and rename the items to their respective OD x WT.

Go to Assembly tab → File, and select the .IGS file of the loading patch locations

Create planes at these locations by creating a reference plane at the origin axes, then using “Move” to move the plane coincident with each of those points

Create a sketch on the plane, ensure layout sketch is turned on, and draw a corner rectangle, snapping from one point to the other. Repeat for the others.

Side note: I realized with the front and rear impact loading pactches, you can just use the front one for both them since they’re the exact same

Create planes that are coincident with the lines of the rectangle. We will use these planes as cutters to split the beams into the sections that will be loaded

With the split feature active, select the beam, and then the plane that was created. Repeat for all the beams that need to be split

Hide the planes, and ensure all the reference points are suppressed for physics and hidden. Finally, under Workbench, select “Share” and click the check mark

Ansys Mechanical Preprocessing and Simulation

Just to ensure there are no underconstrained bodies/issues with the geometry, insert a modal selection into the analysis and solve.

Ensure you have imported your material properties into the Engineering Data.

Apply your boundary conditions and loads to the frame and solve. Just makes sure to scope the force to the beam sections that you cut in the previous step

Altering Beam Profiles

In ANSYS Spaceclaim, navigate to the “Prepare” tab, and select cross section. Then select More Profiles and go to the folder to select your desired beam profile. Select your beam and select a new profile to change the beam cross-section.

Here is the link to download the beam cross-sections: Frame Beam Profiles