Four node element in 3D

[shivanirani11]

Can you please tell me, is there any four node element (tetrahedron) available in opensees in 3D.

[fmk]

no .. if you have a mesh that requires such an element, the stdBrick will degenerate into such an element for you.

[shivanirani11]

can you tell me how can I do that and how much it is reliable

[fmk]

Degenerated tetrahedron elements may be formed from eight-noded 3-D solid elements by defining duplicate node numbers for the third and fifth through eighth node locations. The node pattern then becomes 1 2 3 3 4 4 4 4 instead of 1 2 3 4 5 6 7 8

[wilberk]

Could you tell me if you had any problem with this operation? I am having a difference in frequencies between structures modelled in Opensees with special tetrahedrons and other software with natural tetrahedrons.

Regards.

[wilberk]

Hi, I got to generate tetrahedron elements, but is it possible to generate quadratic tetrahedrons? i.e. tetrahedron elements with 10 nodos?

Thanks,

Wilson