Understanding FEA: A Beginner’s Guide to Finite Element Analysis

Finite Element Analysis, or FEA, is a way to test your designs before you build them. It breaks a 3D model into thousands of tiny pieces called elements. The software then applies math equations to each small piece to see how it reacts to stress or heat. By combining these small results, the software predicts how your whole project will behave in the real world. This process helps engineers find weak spots and fix them early. Using these tools saves time and money by preventing parts from breaking after they are manufactured.

Getting Started with Simulation

To start an FEA test, you must enter the simulation workspace in Fusion. When you open this workspace, you will see several types of studies. Common studies include modal frequency, thermal tests, and electronics cooling.

The most common test is a static stress study. This study checks if a part will bend or break under a constant load. Many other tests require cloud credits to solve because they use a lot of computer power. However, static stress tests usually run on your local computer for free.

Understanding the Mesh

The mesh is the foundation of every FEA study. It is the network of small shapes that covers your model. By default, the software sets the mesh size to about 10% of your model size. You can change this setting if you need more detail. A finer mesh creates smaller elements. This makes the results more accurate but takes longer for the computer to calculate.

You can also use adaptive mesh refinement. This setting tells the software to run the test multiple times. After the first run, the software finds areas with high stress. It then makes the mesh smaller in those specific spots and runs the test again. This leads to a very high resolution result without making the whole model complex.

Simplifying Your Design for Faster Results

You do not always need to test every single screw or hole in an assembly. Testing a full drone with every part takes too much time. It is better to focus on the part you are worried about, like the base plate. You can use the simplify tool to remove everything except the part you want to study.

Removing Small Features

Small details like tiny holes or fillets can slow down the simulation. Every curve requires many tiny mesh elements to calculate correctly. If a feature does not affect the strength of the part, it is best to remove it.

You can use a remove features tool to clean up the model. This tool uses a slider to select features by size. You can quickly delete:

• Small fillets and chamfers.

• Tiny holes

• Small extrusions or logos.

When you delete these in the simulation workspace, they stay in your original design. The software only removes them for the test. This keeps your main design perfect while making the math easier for the computer.

Assigning Materials and Constraints

Every part needs a material assigned to it. The computer needs to know if the part is made of metal, plastic, etc. Different materials have different strengths. For example, a drone plate made of ABS plastic will bend much more than one made of Aluminum.

Setting Constraints

Constraints tell the software which parts of the model cannot move. Think of this like bolting a part to a heavy table. If you do not set constraints, the whole part will just fly away when you apply force. In a drone simulation, you might fix the center area where the battery and electronics sit. This area stays still while the outer arms flex under the power of the motors.

Common types of constraints include:

• Fixed: The face cannot move in any direction.

• Pin: The part can rotate but not move side to side.

• Frictionless: The part can slide along a surface but not move through it.

Applying Structural Loads

Once the part is held in place, you must add forces. These are called loads. In a drone example, there are two main forces to consider. The first is the upward lift force from the propellers. This is a simple force that pushes on the motor mounts.

The second force is torque or moment. This is a twisting force caused by the motor spinning. Adding both the downward push and the twist gives a realistic view of the stress on the arms.

Load Type	What it Simulates	Direction
Force	A direct push or pull	Linear (X, Y, or Z)
Moment	A twisting or turning force	Rotational
Pressure	Force spread over an area	Normal to the face
Gravity	The weight of the part itself	Toward the ground

Analyzing the Results

After you click solve, the software gives you several ways to view the data. The most important result is the Safety Factor. This number tells you if the part is safe. A safety factor below 1.0 means the part will break or stay bent permanently. Engineers usually aim for a safety factor between 3 and 6.

Stress and Displacement

You can also view the Stress map. This uses colors to show where the part is working the hardest. Red areas have high stress, while blue areas have low stress. If you see red around a sharp corner, you might need to add a larger curve, or fillet, to spread the load. Displacement shows you how far the part actually moves. The software often shows an "adjusted" view. This exaggerates the bending so you can see it easily. You can change this to "actual" to see the real movement, which is often very small.

Using Animation and Probes

Animations help you visualize the movement. You can watch the part flex back and forth to see if it twists in an unexpected way. You can also use surface probes to click on any spot and see the exact stress value at that point. If you want to see inside the part, a slice plane lets you cut through the model to view internal stress.

Improving Your Design

If your test shows a low safety factor, you must change your design. You can go back to the design workspace and make parts thicker or change the material. For example, if an ABS plastic plate fails, you can switch it to a stronger material.

After making a change, you can clone the study. This creates a second test with all your forces and constraints already set up. You just run the solve again on the new shape. This allows you to compare the two designs side by side. You can see exactly how much stronger the part became after you added a larger fillet or changed the metal.

Simulating Real World Impacts

FEA is also great for testing crashes. You can simulate what happens if a drone hits a wall at high speed. To do this, you apply a large force to the front face of the drone. In this type of test, you need to use automatic contacts. This tells the computer how different parts in an assembly touch each other.

When you run an impact test, the displacement map shows which parts move the most. You might notice the back of the drone twisting because it lacks support. This information tells you where to add more posts or braces. By testing these "what if" scenarios, you can build a drone that survives accidents.

Conclusion

Finite Element Analysis is a powerful tool for any designer. It allows you to prove your ideas work before you spend money on materials. By breaking models into smaller elements, you can find the exact point where a part might fail. You can test different materials, change shapes, and see the results in minutes.

Learning to use FEA helps you create better, safer products. It takes the guesswork out of engineering. Whether you are building a simple bracket or a complex drone, simulation software gives you the data you need to succeed. Start by simplifying your models and checking your safety factors to ensure your designs can handle the pressure.