How Long Does an FEA Analysis Take?

Geometry is often one of the first sources of additional work.

A simple bracket, plate, shaft, or pressure vessel can usually be prepared quickly.

A complicated assembly may contain:

• Hundreds of parts
• Small fillets and holes
• Fasteners
• Welds
• Thin features
• Complex interfaces
• Imported CAD imperfections

Not every geometric feature needs to be included in an FEA model.

In fact, an experienced analyst will often simplify the geometry before meshing it. Removing unnecessary details can reduce model size and computation time without sacrificing the accuracy required for the engineering decision.

However, deciding what can safely be simplified requires engineering judgment.

FEA divides the structure into smaller numerical regions called finite elements.

Increasing the number of elements generally increases the computational resources required to solve the model.

For example, a model containing 50,000 elements will usually solve faster than one containing several million.

But simply using a coarse mesh to obtain faster results can produce inaccurate stresses or deformation.

The objective is not to create the finest possible mesh everywhere. Instead, the analyst should create sufficient resolution in important regions such as:

• Stress concentrations
• Contact interfaces
• Holes
• Fillets
• Welds
• Load application areas
• Rapid geometric transitions

while using a coarser mesh where additional detail provides little value.

The choice of element type can also affect computational cost. Some element formulations require more computational effort than others, and certain geometries require finer meshes to obtain reliable results.

One of the biggest factors affecting FEA analysis time is whether the problem is linear or nonlinear.

A typical linear static analysis assumes relationships such as:

• Small deformation
• Linear elastic material behavior
• No significant changes in contact
• Loads that do not fundamentally change the structural configuration

These models can often be solved relatively quickly.

Nonlinear models may include:

• Plastic deformation
• Rubber or hyperelastic materials
• Large deformation
• Buckling
• Changing contact conditions
• Friction
• Material failure
• Bolted joints
• Gaskets
• Snap-through behavior

Instead of solving the system once, nonlinear solvers generally progress through multiple increments and iterations while repeatedly checking whether equilibrium has been achieved.

This can significantly increase simulation time.

Contact and material complexity can also lead to convergence difficulties, which may require the analyst to modify the model before obtaining a reliable solution.

Assemblies containing multiple components are often significantly more complicated than single-part simulations.

The analyst may need to determine whether interfaces are:

• Bonded
• Sliding
• Frictional
• Separating
• Press-fit
• Bolted
• Welded

Contact can change during loading.

Two surfaces may begin separated, come into contact, slide relative to one another, and then separate again.

This introduces significant numerical complexity.

Contact settings, mesh quality, stiffness, friction coefficients, and time increments may all affect convergence and computational time.

For this reason, an assembly with realistic contact behavior can take considerably longer than a similar-looking model in which every component is simply bonded together.

Simple engineering materials can often be represented using basic properties such as:

• Young’s modulus
• Poisson’s ratio
• Density
• Yield strength

More advanced simulations may require much more detailed material data.

Examples include:

• Plasticity curves
• Hyperelastic properties
• Viscoelastic behavior
• Creep
• Temperature-dependent properties
• Composite material properties
• Failure criteria

Obtaining reliable material data can itself become part of the project.

If the required properties are unavailable, the engineering team may need to obtain manufacturer data, review literature, make justified assumptions, or perform material testing.

An FEA model can produce mathematically precise results while still representing the wrong physical problem.

That is why defining realistic loads and boundary conditions is one of the most important parts of the analysis.

Questions may include:

• Where is the structure actually supported?
• Is a connection rigid or flexible?
• How is the force distributed?
• Is the load static, cyclic, thermal, or transient?
• Are there preload forces?
• Does pressure vary spatially?
• Are acceleration or impact effects important?

If the customer provides clear design loads and operating conditions, model development can proceed much faster.

If those conditions first need to be reconstructed from drawings, specifications, field data, measurements, or engineering calculations, the FEA project will take longer.