Learning Forum

[Abdoon075]

Hello experts ,,,,, 

I'm going to do a fracture analysis for stiffened panel by using shell element, but I can't complete the pre-meshed crack modeling because I have to select an "Edge" for crack tip when I just have a "Point" (which is the green point in the attached pic.) because the panel is shell element not solid element

please help me ... 

[peteroznewman]

You have to use the Geometry editor to cut a Vee shaped crack into the edge of the sheet. Then you will have two edges that define the crack and a vertex at the crack tip.

[Abdoon075]

thanks for your reply Mr. Peter

When I select the tow edges and create Named selection They didn't defined in details of pre-meshed crack  

[peteroznewman]

I know a crack is supported in a 2D model, I don't know if a crack in a 3D shell models is supported.

Please get some experience using a pre-meshed crack in either a 2D model or a 3D solid model first, then you will know what success looks like.

You must create nodal named selections and you must create a coordinate system in the crack. Please read some ANSYS Help for more information.

[Abdoon075]

In 2D model the crack tip must be a vertex, so the nodal named selection must be a point or a vertex. I tried 2D model and its work correctly. In 2D Model I must model the stiffeners as Line body, because in 2D analysis type I must draw in just only one plane  (X-Y plane). In my case study I assume that the crack will propagate in plate and stiffener together, so I have to model a crack on the stiffener which I can't do if I model the stiffener as a line body. To eliminate the problem  of modeling the crack on the stiffener I have to use 3D model. But When I use 3D I'll face the problem of creating the nodal named selection, because In 3D analysis the nodal named selection must be An edge at crack tip, but when I use shell element I have a point at crack tip 

I read ANSYS help many times, but I didn't fine sol. for my problem   

[David Weed]

Hi, fracture analysis does not support shell elements, see here: https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v195/ans_frac/frac_parmcalcelemmatsupp.html

[Abdoon075]

Mr. David thanks for your response 

I do a fracture analysis by using 2D analysis type. 

[Abdoon075]

Does that mean shell element support the fracture analysis ???

[peteroznewman]

Shell elements do not support fracture analysis.