FEM best practices and examples
FEM-solver
The FEM-solver is written completely in C# with. It is geometrically linear. So second order effects are not taken into account.
Mesh element/theory
The mesh element used with in plates in XFEM4U is a modified Kirchhoff element. It is extended in 2021 by | Professor Blaauwendraad. Usually Kirchhoff is less precise regarding shear force distribution. In the modified element this is solved. Therefore it is a extremely robust element with very reliable shear force distribution.
Mesher
The mesher is using 4-nodes quadrangle elements because they are more accurate than 3-nodes triangle elements. On a edge
Mesh Size
Below we describe a method how to find the right mesh size for your structure. If you make the mesh too dense, internal forces will be higher then reality. First some basics.
- Element size should never be smaller then the plate thickness. Otherwise the theory of Kirchhoff is not correct anymore.
- Element size also at least the smallest spansize in the structure to expect a correct result.
- Steel plate structures: If you make you mesh 50% smaller the stress should not increase more then 10-12%.
Workflow to find the right meshsize within a steel structure.