Analyse a user defined thin-walled seciton

[Anonymous]

Hello mates!

I have read the all the posts I could find related to defining thin walled sections but I could not sort my query. Hence I decided to start a new post.

I am trying to find the warping coefficient Iw for a compound section.

I have defined a compound section 406x178x54UB + 2 300x100x46PFC either side.

For that I have defined the section in the section definition and saved the section to my database.

I have assigned in the Member definition the member to be thin walled.

I have read in previous posts that you advised that next to the section type name a thin walled sign should appear, which I cannot see.

The warping coefficient resulted from robot is Iw = 71956862976 mm6 = 7.2E11 mm6

　

For the 406x178x54UB the Iw value from the table is 3.91E11 mm6 - which is greater than for the compound section calculated by robot which does not make sense. 　

By the way, the value obtained for Iw is the same as when calculated for section without thin walls. (when the thin wall was un ticked.)

Please see the picture attached for clarity.

Many thanks,

Dan

[Anonymous]

Anyone?

[Anonymous]

Edit:

warping coefficient calculated by robot is 7.2E10 mm6 not E11

[Anonymous]

Hello mates!

I have read the all the posts I could find related to defining thin walled sections but I could not sort my query. Hence I decided to start a new post.

I am trying to find the warping coefficient Iw for a compound section.

I have defined a compound section 406x178x54UB + 2 300x100x46PFC either side.

For that I have defined the section in the section definition and saved the section to my database.

I have assigned in the Member definition the member to be thin walled.

I have read in previous posts that you advised that next to the section type name a thin walled sign should appear, which I cannot see.

The warping coefficient resulted from robot is Iw = 71956862976 mm6 = 7.2E10 mm6

　

For the 406x178x54UB the Iw value from the table is 3.91E11 mm6 - which is greater than for the compound section calculated by robot which does not make sense. 　

By the way, the value obtained for Iw is the same as when calculated for section without thin walls. (when the thin wall was un ticked.)

Please see the picture attached for clarity.

Many thanks,

Dan

[Artur.Kosakowski · Accepted solution]

Iw is calculated as per selected section type (I profile) and based on the entered dimensions as explained during the 3rd Robot webinar. 

You may decide ion entering them e.g. in the way shown below:

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.