The Finite Element Method (FEM) is a mathematical technique used to perform Finite Element Analysis (FEA) of any physical phenomenon. Used extensively in various engineering fields, including automotive and aerospace, the technique and FE modelling tools allow engineers to test how structures or parts will react under certain circumstances.

If that sounds quite vague, don’t worry, we’re going to explain it in a bit more detail in this blog, as well as how FEA tools are used in the aerospace industry and how we utilise them at Airframe Designs.

What Is Finite Element Analysis?

Finite Element Analysis (FEA), or the Finite Element Method (FEM) is a software tool used to model, analyse, and test component strengths and reactions under any number of variable conditions (extreme heat or pressure, for example). In aerospace, this enables engineers to test components and predict how they will behave in ‘real life’, usually to structural or thermal loads.

But why? Let’s explain…

If you need to design something new that is going to be subject to forces and pressures, a jet engine part, for example, or part of an aircraft structure, you need to be sure your design is going to work.

You could make a prototype and test it, but what if it’s a new part for which there are no previous designs to improve upon, or you really have no idea how the part will react in certain circumstances? You could run through hundreds of prototypes and end up with lots of failures and little clue as to why your design failed.

You could also use mathematical calculations and equations to work out how your part will react, but doing this without the assistance of software is difficult and time-consuming for even the most talented mathematician!

Through FEA, designers can digitally create a prototype, test it multiple times over, in any number of situations, and understand in detail why something won’t work, or how your design can be improved. All the complex equations and calculations are done by the software.

Physical prototypes are great but aren’t useful in situations where you may need lots of attempts to get a design right and need to understand in detail, what parts of your design aren’t working under what conditions.

FEA takes each part of a design and breaks it down into many pieces, tests them individually and then gives you feedback as a whole.

This is very simplified but that’s generally what FEA is and how it might be applied in aerospace engineering.

The Benefits Of Finite Element Analysis or FEM in Aerospace

We’ve briefly mentioned the benefits of FEA in aerospace design, but let’s look in a bit more detail…

Using finite element models, we can test several elements at the same time (heat and mechanical wear for instance), so the testing of virtual prototypes can be carried out much more efficiently than using other methods.

There are other benefits too when using finite element models in place of physical prototypes:

  • Models can be tested not only in variable conditions to see how they behave but over longer periods too. For example, how would a part wear over the course of five years?
  • Less expense with FEM because no physical parts are manufactured.
  • Testing is much faster than other methods because computers can work faster than humans can!
  • Although specialists are required to conduct FEA, there is a reduction in the number of people and hours required to complete a project.

How Airframe Designs Applies Finite Element Analysis In Practice

Now you know what FEA is and its benefits for the aerospace industry, let’s have a look at a real-life example where FEA was used to help a client meet their objectives.

We were engaged by STC Twenty One a couple of years ago to help support with the relocation of a galley complex on an AIRBUS A330 aircraft.

The challenge was to understand if the floor and monocoque fuselage, once the galley had been relocated, would have the necessary static strength to support the weight of the monuments during worst-case flight gust conditions. We built a finite element model that represented the fuselage surrounding the proposed location of the galley complex and were then able to test this model in various ways including the impact of maximum passenger loading.

In this example, FEA has a clear advantage – there were so many variables, and prototyping anything would have been too difficult. Testing out a galley relocation in ‘real life’ is also not possible! Using FEA, we were able to get the right results for the client – the assurance that their planned aircraft conversion could go ahead, and the finished result would be reliable and meet all required safety regulations.

Got A Project In Mind?

We hope this post has provided an insight into FEM and how we utilise it here at Airframe Designs.

Our team of specialists use FEM in a variety of ways to help clients solve challenging design issues. Our core analysis capabilities cover traditional static stress analysis (hand calculation), finite element modelling, and F&DT (or fatigue and damage tolerance) evaluation.

If you have a project in mind you would like to collaborate on, please get in touch!