significance element settings

Altair Forum User

Team,

What is the difference b/w shortest edge, minimal height and normalized height under check element setting panel and its significance?

Altair Forum User

Hi,

Minimum element lengths are calculated using one of these methods:

•The shortest edge of the element. This method is used for non-tetrahedral 3D elements.

•The shortest distance from a corner node to its opposing edge (or face, in the case of tetra elements); referred to as 'minimal normalized height'.

• Minimal height, which is the same as minimal normalized height but without a scaling factor.

Each check can be set to use a different solver’s check method, or user can set every check to use the same method.

Please go through the Help Menu on the same for more description on this topic.

Altair Forum User

Thanks for update.

> what is not tetra. you mean to say 2D and hex?

>minimal normalized height & Minimal height you mentioned it is for tetra elements. It means if we have a crash model having a shell elements then we can not use these options.

> In Radioss model time step(L/c) is calculated based on which L-Min element size(shortest edge, minimal height and normalized height ).

 

I haven't find and significant related to above in help menu please share a link or forward:

Altair Forum User

Hi Sumit,

• Yes.
• The minimal normalized height is applicable  for shell elements also. Just as a case or example tetra was mentioned in the above post.
• For RADIOSS, it normally takes the shortest edge to calculate.

      Please find the attached document on the same.

Unable to find an attachment - read this blog

Altair Forum User

Thanks for reply.

>Now what is scaling factor in minimum height option? How to decide the same? Can you share some pic showing minimum height in element just like it is mentioned in minimal mormalized height?

>Can you share some document showing Radios consider shortest edge to calculate time step? And if it can be change then what factors makes one to consider while selecting shortest edge, minimal height and normalized height for calculating minimum element size?

Altair Forum User

Hi Sumit,

In the above shared document it is written that the scaling factor used is 2/sqrt(3.0). Unfortunately we don't have much documents on this currently.

Please go through Shell Elements in RADIOSS Theory Manual where this concept is explained.