FEA simulation strategy: 10 steps first

Developing a finite element model is a lot like playing a game of chess: it demands anticipating problems, predicting how the structure will behave and adapting a strategy in advance. Many engineers make the mistake of opening the preprocessor straight away and starting to create elements with no prior planning. Yet having the most advanced FEA software in the world is worthless if the problem hasn't first been analysed with pencil, paper and sound engineering judgement.

Finite Element Analysis (FEA) is an extraordinarily powerful tool for solving complex mechanical problems, but it is not a quick method. To avoid rebuilding expensive models or accepting numerically wrong results as valid, it is essential to follow a systematic methodology before pressing the meshing button. Below are the 10 master steps for defining a robust simulation strategy — the natural precursor to the 7 steps of the Finite Element Method.

Step 1: Set out the problem and align expectations

The FEA analyst is rarely the only user or recipient of the analysis. The first fundamental step is to meet with clients, designers or project owners and communicate openly. In this phase the purpose of the model must be made clear, making sure every stakeholder understands both the real capabilities of the method and its implicit limitations.

Step 2: Define clear objectives

You need to formally answer the question: what exactly must the model capture? Depending on the goal, the modelling assumptions will change radically:

Are you evaluating global stiffness or deformation under load?
Do you need to compute stress peaks at localised concentrators (hot spots)?
Do you intend to extract loads at interfaces and joints?
Will you assess fatigue, buckling/instability, heat transfer or nonlinear effects (material, geometric or contact)?

Defining the objectives precisely determines which element types to use, what level of refinement to apply and which solver to run.

Step 3: Analyse the structural history

Almost any component you analyse has a background or comes from a previous design. It is key to examine how similar parts have behaved in service, study earlier failure reports, review test reports or even watch videos of the component in operation. This lets you identify known weak points and build into the model the physical phenomena that actually govern the component's life.

Step 4: Assess feasibility and the combination with testing

Before moving on, ask whether FEA really is the best way to solve the problem. If the objectives cannot be reached through simulation, be honest and propose alternatives. Combining physical tests with FEA is one of the most powerful strategies in engineering: experimental data allows you to calibrate and validate the assumptions of the numerical model.

Step 5: Assess the environment and the boundary conditions

You need to analyse the surrounding structure to determine how much physical context must be included in the simulation. Boundary conditions are the factor that most influences the model's behaviour and one of the biggest sources of error. A good practice is to plan test runs of the model with different boundary-condition variants, in order to bracket the solution and assess the sensitivity of the peak stresses.

Step 6: Understand the loads and predict the load path

The fundamental purpose of a structure is to transfer forces from the points where they are applied to the supports. The route these forces follow through the components is known as the load path.

In simple statically determinate structures, the path is obvious.
In statically indeterminate or redundant structures, the load distribution depends directly on the relative stiffness of each member.

The analyst must be able to predict the load path qualitatively before simulating; otherwise there is no way to judge whether the software's behaviour is physically consistent.

Fig. 1 — The load path: force F enters at the top vertex and travels down the inclined members to the reactions R₁ and R₂. If you can't predict this route before simulating, you can't judge the result.

Step 7: Select the element type and the model size

This step is about balancing model development time, required accuracy and computational cost. It is critical to keep in mind the scaling laws of the numerical method:

The memory required by the model grows with the square of the number of nodes (N²).
The solver's solution time grows with the cube of the number of nodes (N³).

Memory ∝ N² · Solution time ∝ N³

That is why you must decide when it pays to abstract the geometry with 1D elements (bars and beams) or 2D elements (shells) instead of saturating memory with 3D solid elements.

Step 8: Predict the final results

Before running the calculation (solve), the engineer must anticipate the deformed shape the structure will take. Sketching the expected deflections by hand forces the analyst to think through the physics of the problem and stops them from accepting — or trying to justify — an incoherent numerical result caused by an error in the supports.

Don't let the software “predict” the behaviour for the user: the user must guide the software.

Step 9: Review the plan and prepare the report

Before starting the modelling in the software, it's time to pause and review every assumption:

Does the plan satisfy all of the originally stated objectives?
What questions will come up during the design review?
What output formats will be needed (contour plots, line plots, reaction vectors, free-body diagrams)?

Anticipating how results will be presented lets you prepare the defence of the assumptions used and avoids having to repeat the analysis from scratch.

Step 10: Answer the 14 key questions before modelling

As a final checklist, the analyst should be able to answer the following questions clearly:

Are the objectives of the model clearly identified?
What type of solution will be used (static, modal, nonlinear, etc.) and is it consistent with the problem?
Is the source CAD geometry reliable, and is it known how to simplify it?
Can the choice of element types be fully justified?
Which boundary conditions will be applied, and why?
Are the nature and magnitude of the loads thoroughly understood?
Have the main load paths in the structure been identified?
Has the structure's response or deformed shape been anticipated qualitatively?
At which specific locations will the numerical results be extracted?
What margin of accuracy or error is acceptable for the stated objective?
Are all the modelling techniques defined (joints, contacts, transitions)?
Have the points of geometric discontinuity in the structure been located?
Are all the capabilities and limitations of the model to be built known?
Is there any potential source of nonlinearity (geometric, material or boundary)?

Conclusion

Finite Element Analysis is not just about knowing the buttons of a piece of software, but about understanding the physics behind the simulated structure and the real behaviour of its components. The software works as a “black box” that solves large systems of algebraic equations. If the engineer hasn't mastered planning techniques and modelling assumptions, they will end up handing the solver an incorrect system of equations, and get wrong answers under a flawless graphical appearance.

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