FEA provides an accurate response of a structure from imposed loads and constraints
Summary
Written for non-engineering audiences – a basic introduction to Finite Element Analysis (FEA) covering the digital modeling process, meshing, load and constraint application, and interpretation of stress and displacement results.
What is Finite Element Analysis (FEA) ?
Finite Element Analysis (FEA) is a computer simulation technique used to evaluate whether a component or system will hold up under real-world conditions — before it’s built, tested, or put into service.
In practice, an engineer creates a digital model of the structure and subjects it to the forces it will actually experience: mechanical loads, temperature changes, vibration, seismic events, or internal pressure. The software divides the model into thousands of small segments — called finite elements — and solves the governing equations across each one, showing where stress concentrates, where deformation occurs, and where failure is most likely to begin.
FEA can handle both simple and complex geometries, and it accounts for materials that respond predictably under low loads as well as those that behave differently once stress exceeds a threshold. When done right, FEA is an efficient tool for evaluating structural integrity, particularly for complex geometries and loading conditions where hand calculations fall short. It doesn’t replace physical testing or classical engineering checks — it complements them, often at a fraction of the time and cost. O’Donnell Consulting has applied FEA for over 30 years across industries ranging from nuclear power to petrochemical, using it to support equipment design, code compliance, failure analysis, and expert witness work.
For more details, see History of Finite Element Analysis.
Why Do I Need FEA?
Finite element analysis, when properly applied by experienced engineers, provides an accurate response of a structure from imposed loads and constraints.
Typical reasons why FEA is performed:
- For a manufacturer who is required to meet specific structural codes and standards.
- As a plant owner/operator – it is a useful tool for helping to identify the cause of a failure and perform subsequent redesigns.
- For an agent involved in litigation, FEA (where applicable) is used to develop models to clarify the root cause –
enabling attorneys to easily understand the technical issues.
What’s Involved in Performing a Finite Element Analysis?
The analysis starts with a digital model of the part or structure, usually built from the same 3-D CAD drawings used to design or manufacture it. The software divides that model into thousands of small, simple pieces called elements, a step known as meshing. The dam gate model shown above is an example: the gate is broken into many small three-dimensional blocks. Each element is simple enough that its behavior can be calculated directly, and the software connects all of them so that together they behave like the entire structure. Getting the mesh right is one of the most important parts of the job. Elements that are too coarse in critical areas can miss the very stresses the analysis is meant to find.
The engineer then tells the model what it is made of and what it will face. That means the material properties, the loads it must carry (weight, pressure, temperature, or vibration), and how it is supported or held in place. The software solves the equations for every element at once, a calculation that would be impossible by hand. The computer does the arithmetic. The engineer’s judgment decides what goes into the model, and whether the answer that comes out makes sense.
The demonstration below walks through these steps one at a time.
What Do I Get out of a Finite Element Analysis?
Analysis results are most commonly presented as color contour plots and or displaced shapes of the result(s) of interest (e.g. stress level or displacement magnitude, etc.). With this approach, critical regions can quickly be identified. The quality of FEA results is highly dependent on the quality of the input data. FEA models/analyses results should always be assessed against results obtained with classical engineering equations or other known solutions.
The Bottom Line….
More and more, product suppliers and end users are recognizing the benefits of FEA and are requesting this type of design assessment from manufacturers and fabricators. With the ever-increasing speed of personal computers and accessibility of cloud-based computing to both individuals and large corporations, FEA has become a standard tool for anyone involved in design/ component/ system/ structure evaluation. Software companies are responding by integrating simulation tools directly within the CAD environment along with the ability for “instant” simulation.
As with any other tool, it is important to understand the limitations and proper use. Anyone can perform a finite element analysis. However, getting it done right requires attention to detail and a critical eye.
