Hybrid elements

[BW94]

Hi everyone,

I have a question related to the stress and strain output variables for hybrid elements;

Do stress and strain output variables differ for hybrid elements compared to non-hybrid elements, or are these output variables just calculated in a slightly different way but with the exact same outcomes?

In other words: do stress and strain output variables differ when I indent a homogeneous, linear elastic material built from hybrid elements compared to the same situation but with normal elements?

Some simple tests indeed give the same results for hybrid elements and normal elements, but I was wondering if there could be an actual difference in some cases.

thanks in advance!

 

[FEA way]

Hybrid elements are meant to be used for almost incompressible and fully incompressible materials as well as in situations when strains reach far into plasticity regime what causes volumetric locking. They are formulated in such way that they should provide more accurate answer to these problems thanks to the fact that they eliminate volumetric locking. The basic difference between hybrid and regular elements is that hybrid ones use independent interpolation for hydrostatic pressure.

You can find more detailed description, including the formulation of these elements, in the documentation.