hybrid elements

[navigator30]

I'll try my question in a separate thread, maybe anyone can anwer it.
I read abaqus documentation a couple of times now, but haven't quite gotten it wether to use hybrid elements for an elastomeric material or rather reduced integration elements. The material is subjected to shear forces, would that do some hourglassing effect (if reduced integration effect), or does hourglassing only refer to bending shear??????

I can' get that quite clear.

THanx for answers!

 

[xerf]

In general the hybrid elements are used for incompressible materials to avoid volumetric locking.

Hourglassing is a spurious deformation mode. The element deforms but the strain is zero. It typically can occur in first order elements with reduced integration and first order hybrid elements.

If you plot the deformed mesh (maybe with some scaling factor >1.0), you can recognize the hourglassing effect by the characteristic deformed shape of the elements (i.e., two neighbour elements will look like an hourglass I><I><I).

If the material is near incompressible you shoud try to use hybrid (mixed) elements to avoid volumetric locking. You will have to check afterwards if the solution developed hourglassing and locking and modify your model to eliminate them.

 

[navigator30]

thanx, xerf!