Finite Element Accuracy Criteria

Hello to everyone,

i want to ask, if there is a possibility to create accurcy criterias or plots of the accuracy of the mesh like in the attached document. Or how can i check if the mesh pass the named criterias from the document?

Thanks and greetings,

Beginner

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Pranav Hari

Hi Beginner93

You can do a quality check in Hypermesh to see whether your mesh has passed it. Tools > Check elems

Have a look at the e-book 'Practical aspects of finite element simulation'' (https://altairuniversity.com/free-ebooks-2/free-ebook-practical-aspects-of-finite-element-simulation-a-study-guide/)

Refer page 309 where element quality checks are explained in detail

Ovando_RBB

Hi there,

That's a great question that should be part of the FE foundations, and one that every analyst should ask when working with finite element methods.

First, it’s important to distinguish between convergence and accuracy, two concepts that are often confused in FEA modeling.

Convergence refers to the numerical stability of your solution. It is governed by the truncation error, which measures how closely your discrete model approximates the underlying mathematical equations. Long story short, when running an FEA simulation, the solver iteratively refines the solution until the difference between successive iterations falls below a specified (by the analyst) numerical tolerance, this is where truncation error serves as a threshold.

However, converging a solution doesn't guarantee that the solution represents properly the reality and nature of the phenomena that it’s been analyzed. You may achieve convergence while still producing a model that misrepresents the natural behavior of what it is observed in the reality. This is where accuracy becomes critical.

To evaluate the accuracy of your FEA model, a mesh sensitivity study is essential. This involves running the same simulation with varying mesh densities, commonly categorized as coarse, fine, and very fine, while keeping all other modeling parameters constant.

If your key output variables (e.g., temperature, flow velocity, stress, displacement, voltage) exhibit little to no change as the mesh becomes finer, it’s a strong indication that your model has been well resolved. On the other hand, if significant differences remain between the fine and very fine meshes, this suggests that the existing mesh is still too coarse to capture the physical phenomena with accuracy.

In such cases, further mesh refinement or adjustments to the model setup (e.g., boundary conditions, element types, or solver settings) may be necessary to improve both resolution and confidence in your results.

Hope this comment helps!