Excessive Distortion in VUHARD !!

Dear Friends,

I wrote a VUHARD for a dynamic explicit analysis. Something is going really very strange:

For a model with just a few elements it works,

But:

For the same model with finer mesh it is encountered to ''Element Excessive Distortion'' !!

Does anybody have any idea about that?

I would be happy to let me know.

Greetings,
Hassan