SimScale CAE Forum

Finite Element Analysis Process


#1

The following six steps are essential to know in order to understand what the (mathematical) approach of the FEA is:


First step:

Preprocessing:

  • Create geometry
  • Defeature small unnecessary details in the model (\rightarrow careful since this is a source of errors)
  • Make use of symmetries - not possible if the load is not symmetric
  • Fillets used in the model may lead to stress singularities (“sharp re-entrant corners”)
  • Define material properties
  • Linear material behaviour is straight forward
  • Elastoplastic material (Hardening rules, behaviour beyond yielding, etc.)
  • Isotropy - Anisotropy
  • Choose initial and boundary conditions
  • Master-Slave Assignment
  • Define (if necessary) side conditions like contact definitions
  • Discretization of the geometry \rightarrow Meshing of the components
  • First Order & Second Order Mesh

Pre-Analysis Checks:

  • Consistent units (Young’s Modulus, Dimensions of the components etc.)
  • Check loads and boundary conditions
  • Check Mesh Quality visually (some softwares offer an automatic Mesh Quality Check)
  • Check Element Types / Accuracy
  • Check Contact definitions if necessary
  • Check that you only write the results you need

Second step:

  • Element formulation \rightarrow development of equations for elements

  • Set up the partial differential equation in its weak form


Third step:

Assembly:
Set up global problem \rightarrow obtaining equations for the entire system from the equations for one element.


Fourth step:

Solving the equations (solve system of linear equations).


Fifth step:

Postprocessing:
Determining quantities of interest, such as stresses and strains and obtaining visualizations of the response.


Sixth step:

Post-Analysis Checks to verify results:

  • Check if the deformed component looks as you would expect
    \rightarrow Pay attention to the scaling!

  • Convergence Study (“Does a finer Mesh have significant influence on the results?”)

  • Compare simulation results to analytical solutions if available


For general information about errors and singularities in FEA, please have a look at our blog post:

Errors in FEA and Understanding Singularities (Beginners’ Guide)


Read more about the Finite Element Analysis in our dedicated article in the SimWiki.

Also see our SimScale Simulation Wiki for more about other interesting simulation related questions.