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by thschrader
Wed Jun 28, 2017 5:11 pm
Forum: FEM
Topic: using nonlinear material ==> *plastic command
Replies: 50
Views: 4680

Re: using nonlinear material ==> *plastic command

attached a 3D too, but I get some very strange linear results. A face seams fixed but has no fixes ?!? Attached the file ... frame_real3D-problem.fcstd Bernd, I just ran yout 3D-linear example. Ive got no problems, deformation plot seems reasonable, see pictures (linear model). Symmetric/asymetric ...
by thschrader
Wed Jun 28, 2017 3:37 pm
Forum: FEM
Topic: using nonlinear material ==> *plastic command
Replies: 50
Views: 4680

Re: using nonlinear material ==> *plastic command

bernd wrote:
Wed Jun 28, 2017 1:17 pm
thschrader wrote:
Wed Jun 28, 2017 10:50 am
yesterday late evening a ran a calculation for the beam with yellow line fixed
in z-direction (for stabilizing the beam). Strange result....
Would you post the file ?
heres the file.
beam2_plastic_bilinear_to_bernd.FCStd
(13.96 KiB) Downloaded 36 times
Mb= moment at fixing, M1=moment at field ==> sigma
Thomas
by thschrader
Wed Jun 28, 2017 10:50 am
Forum: FEM
Topic: using nonlinear material ==> *plastic command
Replies: 50
Views: 4680

Re: using nonlinear material ==> *plastic command

I forgot:
yesterday late evening a ran a calculation for the beam with yellow line fixed
in z-direction (for stabilizing the beam). Strange result....
Thomas
squeezed.PNG
squeezed.PNG (256.94 KiB) Viewed 666 times
by thschrader
Wed Jun 28, 2017 10:40 am
Forum: FEM
Topic: using nonlinear material ==> *plastic command
Replies: 50
Views: 4680

Re: using nonlinear material ==> *plastic command

bernd wrote:
Tue Jun 27, 2017 11:14 pm
attached a 3D too, but I get some very strange linear results. A face seams fixed but has no fixes ?!? Attached the file ...

frame_real3D-problem.fcstd
Bernd, nice screenshots!
I will have a look at it next weekend, at the moment
Im very busy at work...
Thomas
by thschrader
Tue Jun 27, 2017 9:13 pm
Forum: FEM
Topic: using nonlinear material ==> *plastic command
Replies: 50
Views: 4680

Re: using nonlinear material ==> *plastic command

The interesting thing is, that plastic hinges are only defined for 2D-frameworks, not for 3D.
As far as I know. Ive never seen a 3D-example. so lets take a 3D-system like below and see
what happens...
Picture taken from from
https://www.youtube.com/watch?v=wAJe1R5NDGw
Thomas
3D_framework.png
3D_framework.png (321.63 KiB) Viewed 708 times
by thschrader
Tue Jun 27, 2017 8:42 pm
Forum: FEM
Topic: using nonlinear material ==> *plastic command
Replies: 50
Views: 4680

Re: using nonlinear material ==> *plastic command

Sorry, I was wrong, moments are not equal. Misunderstood my engineering-tables.
But its ok, system will be stable when getting two plastic hinges at the fixings.
Thomas
load.PNG
load.PNG (4.4 KiB) Viewed 713 times
bendingmoment.PNG
bendingmoment.PNG (6.19 KiB) Viewed 713 times
by thschrader
Tue Jun 27, 2017 8:20 pm
Forum: FEM
Topic: using nonlinear material ==> *plastic command
Replies: 50
Views: 4680

Re: using nonlinear material ==> *plastic command

produces a plastic hinge at the fixing, the structure will collapse, the deflection at the tip "runs away". I try an other modell... yeah a frame system would be a much cooler example. you could have 4 hinges before a colaps. you could use much less elements than you have used and get good results ...
by thschrader
Tue Jun 27, 2017 7:13 pm
Forum: FEM
Topic: using nonlinear material ==> *plastic command
Replies: 50
Views: 4680

Re: using nonlinear material ==> *plastic command

runtime several hours? gosh... My second calculation with automatic time increment = off (increment set to 0.05, 20 steps) terminated after 14 steps (1400 sec runtime) with "solution seems to diverge". But I think its not an intelligent modell I use for plastic calculation. When ccx produces a plast...
by thschrader
Tue Jun 27, 2017 5:56 pm
Forum: FEM
Topic: using nonlinear material ==> *plastic command
Replies: 50
Views: 4680

Re: using nonlinear material ==> *plastic command

Hi Bernd,
heres a first result using automatic time incrementation with 0.17.11455.
runtime 3800 sec :shock:
runtime_autom_increm.PNG
runtime_autom_increm.PNG (58.75 KiB) Viewed 560 times
automatic_time_incrementation.PNG
automatic_time_incrementation.PNG (303.83 KiB) Viewed 560 times
by thschrader
Tue Jun 27, 2017 12:10 pm
Forum: FEM
Topic: using nonlinear material ==> *plastic command
Replies: 50
Views: 4680

Re: using nonlinear material ==> *plastic command

hope so too... :)

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