What is Finite element analysis (FEA)?

Let’s say that we want to study how a cube-shaped block of wood would crack up when hit with a hammer. We can simply take a wooden block and hit it to see what would happen. The cube might crack up or even break into pieces, depending on how hard we hit it. But we won’t be able to see the miniature crack patterns inside the unbroken pieces of wood.

But if we can build a cube using Lego-shaped miniature pieces of wood and hit it with a hammer, we can then take the pieces apart to see how the cracks propagate inside. This can help us understand the physics behind how each force affects the material and shape, and help us improve the design.

This is how FEA works. We replace the whole geometry of the object with smaller finite elements and we analyse each element after performing tests. The smaller elements need not necessarily be cubes. It can be any shape, depending on the whole geometry. When we solve problems using FEA, the results are approximate and they are often verified by other methods. The accuracy of the answers depends on the size of the finite elements. But they will confirm the performance of the product.

FEA is done computationally using CAE tools. Consider the following image:

Here, a beam is subjected to finite element analysis to understand how it will react to stress. The different colors denote the varying amount of stress acting on the beam. As you can see, the higher end of the bar (colored pinkish red) has the maximum amount of stress. This means that this specific area is prone to damage more than the other areas. So we can improve the design by:

• Finding the cause of stress and eliminate or reduce it.
• If it’s unavoidable, we can make a particular region thicker to withstand the stress.
• Or we can replace the material with another material that has increased durability.

There are many other solutions as well, depending on the purpose and design of the beam.

If we haven’t performed FEA and rather used the same product on a prototype, we would have arrived at the same conclusion through the harder way. We will have to then re-design the prototype and test it again, which is time consuming and economically tight. Performing FEA helps us to find the problems with the design and solve them before it is made into a prototype, to save time and money.

FEA can be performed in two areas:

The ultimate goal of FEA is to completely eliminate prototype testing and make the whole process virtual. We are still a long way behind that. Yet, a lot of companies are working their way towards it.