A2. What is a finite element?

A2. What is a finite element?

The resolution of the efforts in the elements is carried out following the calculation of the node displacements. The method is specific for each type of element and depends on the software used.

However, the main principle is common to all software, it consists of "isolating" an element to calculate the forces at the Gauss points from the nodal displacements.

The position of the Gauss points is normally specified in the software documentation; in the case of a 4 node shell element as below, they could be located at a distance from the edge of the element equal to about 1/5 of its width.

Example of a 4-node element

The efforts in the center of the element are calculated as the average of the forces at the Gauss points, the efforts at the nodes are extrapolated from the Gauss points.

To summarize, the software calculates:

These calculations are carried out for all the elements. In the end, there are as many efforts at the nodes as there are elements connected to this node (here 4 elements E1 to E4 connected to node n1).

We can then deduce:

Main remarks concerning common usage

Example of a load on a bridge slab illustrating the differences in results during a FE calculation.



Révision #2
Créé 19 September 2023 15:00:02 par Paul Terrasson Duvernon
Mis à jour 10 October 2023 09:42:15 par Paul Terrasson Duvernon