Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations KootK on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Avoid the interpenetration between the elements

Status
Not open for further replies.

DavideITA

Aerospace
Dec 14, 2014
14
I created this model with four plate elements that meet at the center. When viewing the thickness, the elements are interpenetrating, and consequently I note an undesirable increase in weight. It would be possible to keep this geometry avoiding the extra weight? Thanks.
 
 http://files.engineering.com/getfile.aspx?folder=ee30ba6b-79a8-42eb-8c65-3fefce4b67f7&file=No_thickness.jpg
Replies continue below

Recommended for you

your pic showed nothing to me ... only a large cross-hair which might be edges of plate elements ?

i don't quite get your problem. you're making plate elements, in-plane ? then how do they "interpenetrate" ? wouldn't they butt up against each other ?

where are the loads ?

another day in paradise, or is paradise one day closer ?
 
You could adjust your FEM weight by updating the material density or by directly updating the Non-Structural Mass on the plate elements to match the mass you want.

Regards,


Seif Eddine Naffoussi, Stress Engineer
33650 Martillac û France
 
Thank you all for the answers . In the attached link there is ( I hope) a clearer view of the problem that I have set out in the first message .
Regards.

Link attached
 
that is a better view of th eproblem. the "interpretration" is only because you're modelling a 3D shape (a thick plate) with 2D elements. There's nothing you can do (short of modelling with 3D elements) to avoid this. You should not change the thickness of the interferring elements. I guess you could change one pair of "wings" so that you have one pair of the cruxiform being continuous across (like you have) and the other pair stops at t/2 from both sides of the center line (so there's no interferrence) and then have rigid elements connect the mess together; this is probably not a good way to model this.

another day in paradise, or is paradise one day closer ?
 
Thank you for your response. Actually to solve the problem, I will insert an element beam at the center of the cross, rigidly connecting its nodes to the wings. Modeled with solid elements required too many elements even if it would be the best solution.

Link
 
IMO, this is just a visual problem; personally your 2D model would be just fine. adding the RBEs complicates the model, and I don't think will change the answers, though it does improve the optics of the model. if the optics annoy you, don't plot the shape (just the elements).

another day in paradise, or is paradise one day closer ?
 
then you will need to remove the CQUAD elements connected to the RBE2 because high local stress will appears...and this should be avoided...

Seif Eddine Naffoussi, Stress Engineer
33650 Martillac û France
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor