Abaqus - Cohesive Elements & Tie Constraints Tutorial
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- Опубликовано: 5 фев 2025
- This tutorial shows a 2D model using cohesive elements pulled apart. The parts are joined to the cohesive layer using tie constraints and surface to surface contact properties are used to ensure that parts do not intersect. The STATUS field output is used to remove the failed cohesive elements.
good stuff. hard to learn about this from only the abaqus documentation. The hardest part will be getting good values for the material properties for the cohesive elements.
did you figure out where to get these values ..do we need to perform some material characteristic thing or its just random hit and trial we need to do until we reach optimum desired results
Hi,
I just watched few tutorials of yours out of curiosity. And I have to say your Abaqus tutorials are really great and right to the point.
Thanks!
Thanks a lot, that's the nicest message I've received here. So long as somebody appreciates the videos I will keep making them.
Hello everybody. First thanks for a great video and second I do not know if it is still actual for you but if you deal with error: too many attempts made for this increments I have a solution for you. Just increase number of attempts for an increment. To do so: go to step module then in main menu bar choose other- general solutions control manager then click on edit- continue, toggle specify, in Time incrementation bookmark choose first more and increase a number for IA. It should help.
your channel is great. I hope more material. Thanks
Thank you! Excellent tutorial.
Thank you so much this helps for my thesis. What units do you use for Enn etc?
Hi! It's a nice demo! I have one question: why you still set contact between the top part and bottom part? Is their contact possible when there is a cohesive layer between them? Thanks!
Hello, thank you so much for the tutorial, which are the units for the cohesive elements parameters? Thank you in advance
really like your simulation videos. Would you like to creat a modell of crushable foam? Looking forward to that!
hi Landoflemon
let me first to express my deep grateful to this video as it is goes directly to the core points with excellent explanation of why and how ... I hope to see more videos such as this one and keep it up ... just want to know of you have something about CFRP presentation in ABAQUS ... great thanks again
To everyone who has commented about the model not running, I'm sorry that you have had problems with it. Other people have commented with various ways around the convergence problem. The way this video was recorded was I actually recorded the solution first, after building the model but not recording that, then I go back and record my method for building the model to run the simulation. This leaves room for error and it looks like I missed something the second time I built the model.
how you obtained nominal stress value for both directions for cohesive material?
Thank you so much for this video@landoflemon. It is a very nice practice for me.
Does anyone know where to get the values used for the material properties of the cohesive elements?
only through literature survey
I followed your model carefully. The modeling itself is good, but crashes halfway to separation. The problem is the convergence of the contact between top and bottom. Solution:
Reduced initial step size and increased number of increments
Element type : I tried CPE4 or CPE4R both work
BC-2: I added 0 for U1 and UR3
Contact Controls: Automatic Stabilization
Apply contact controls to interaction Int-1
Thank you for the tutorial. It helped me quite a bit.
Bastiaan van der Vossen It works. Many thanks Bastiann!!!
And Thanks for the great tutorial! Ianndoflemon
Hey sir,
After i followed your steps, i cant see the failure of bonding line. How can i see it?
thanks in advance
That's it!! Solved the issue for me! Thank you
What if cohesive element region is only a small part when compared to the top and bottom? How to define master surface as a small region of the top and bottom layers ?
Hello landoflemon ,
I tried all the optionS commented here, but nothing works, still too many attemps for this increment. Did anybody solve the problem in a different way?
Thank you so much
thank you for the video tutorial
Time steps should be smaller, and the dynamic analysis (with mass) should be used, as inertia plays a role in this case.
Thanks a lot for the suggestion Adam
such a complicated process, I want to hand edit the input file ..... our models are nealy 8 to 10 million elements. So obviously, we do not use Abaqus-CAE for modeling purpose. I would have appreciated more if you had shown the input file, as well. Anyway, I say thank you
Thank you for posting all of these great videos. They have helped me enormously. One question though, any idea what would be the best way modem plastics where the molecular orientation plays a big role in strength.
always like your tutorial, very good. a question here, why you choose plane strain type when you generate meshes of bottom? and why you choose quad- structure when you do the cohesive? thank you very much!
Hi sir,
Excuses me.
Could you tell me?
How to do abaqus cohesive 3D elements
ex. Two plates+cohesive
Thanks.
How to create cohesive element between 3D shell structures ? I tried to make the cohesive as 3D shell .. but in element type there is no cohesive.
Hi Sir,
Is it necessary to define the orientation? or negligible? Thank you in advanced for your help.
shouldn't it be plane stress element since the thickness is very small?
Hey. Thanks for the video. Do you know how to apply line load on a shell element beam, if the load is acting outside of the beam? I am struggling with this for a while.
Hello, I am trying to analyze a pavement structure with the different level of the interection between two pavement layers. There are some way to control the Tie level between two parts?thanks
Thank you for your video. i followed steps got converged solution. but i could not get separation and element deletion.
Hi sir, I’ve seen your tutorial that was really helpful but I have a problem in mesh part. When select ok to mesh (for cohesive part) I receive an error which is said that the highlighted element have been determined to have unusable quality using simplified (fast) analysis checks. I don’t know what it means can you help me??
Hi thanks for your video. I have followed exactly what you have done but I am getting error (Too many attempts made for this increment). Could you please help me how to resolve this.
I had a similar problem when I first tried, my problem was that I'd not setup the tied constraint correctly. Ensure that the Master surface is on the metallic part, and the cohesive surface is the slave. That fixed the problem for me.
Sam Abd I am also getting same error.
Try changing plane strain elements from CPE4R to CPE4 (uncheck reduced integration when you select element type).That solved the problem for my model.
Good luck
Fereshteh Sabet Thanks for the suggestion, I hope this helps others.
+Fereshteh Sabet this didn't help me :( thanks for the input though.
hello, thank you for the video, its really good detail, i just have a question i am knew to abaqus and i am trying to model a composite singe lap joint using cohesive elements and tie constraints for the adhesive in the bond area, i am just not sure how to find some of the values, like (E/enn) (G/ess) etc. as well as the fracture energy. Can you give some insight into this matter? Thank you so much.
Hello, if you can't find those values from literature for the particular adhesive you are using, you will have to conduct mechanical tests to get the specific values. You could also do mechanical tests on a lap joint, and then tune the numerical material properties until the model begins to behave like the experiment.
this web is not found,can you send a new web or tell me how to get the vales
Thanks for the tutorial, it is amazing. I have one question: If you translate parts into position instead of doing point to point constraints, does it change anything? Thanks!
"Too many attempts made for this increment" this is the error i am receiving, what should i do now
*I hope my late answer might help future viewers*
I stumbled upon this problem as well, and I believe this is a general non-linear solver problem. At a certain point, the solver can't take another step and it stops after trying to many times. This could possibly be because of 1000 of reasons. What I found in my case, was that I got the stiffness of the cohesive elements wrong somehow and these elements were deforming way too much (maybe 500 times their length). So my advice is to go into the results and step to the last increment that was computed to see if anything looks funky.
I am modelling bonded interfaces using cohesive element and trying to define the values of Nominal Stress(Normal-only Mode), Nominal Stress(First Direction) and Nominal Stress(Second Direction) for "Damage for traction separation laws"(Maxs Damage) and define.
Where can I find the values of these terms, i.e. Nominal Stress (Normal-only Mode), Nominal Stress (First Direction) and Nominal Stress (Second Direction)
I have the same question.
Hi thanks for this very helpful video.
I am trying to run my model however I get the following error "The node numbering might not be correct for element 321 instance coh-1" and this error is reoccurring for many elements. Do you know where I might have gone wrong. Bare in mind I'm modelling in 3D (swept). Thanks
I'm afraid I've never encountered that error and I don't understand where the problem would be. It's certainly very strange.
please share a full detailed video
i have a question here. He takes plane strain thickness as 1 in the section module. However other dimensions are 5 and 75. So to be plane strain, thickness must be much more than 5 isnt it? Or am i missing a point??
Hi, yeah in this example the thickness is much greater than the other dimensions. Just the way I did that example. I normally model carbon fibres and just used to doing in that way, where the length of the fibre is much greater than the diameter.
thanks for the quick response, i am dealing with GFRP specimen, and trying to model delamination with cohesive elements, and my dimensions are like 6mm length and 2.7 mm layer thickness. And the 3rd dimension is like 6mm again. I was putting 1 all the time for plane strain thickness and out-of-plane thickness for cohesive section. So do you think i should put 6 instead of 1 in my case? Regards
I think you could take it as either, but if you take it as '1', then you'll have to account for that in the resulting stress, as your cross sectional area would be lower.
the video is great,but i still cannot get the results exactly，why??
thanks a Lot.
you Realy Helped me.
Hi , thanks for your useful video , I wanted to expand this work and have a 3D module so I followed exactly what you do in this video , but in visualization module the cohesive elements did not vanish like 2D module , however I active status in step module , I appreciate you if you help me to remove my problem
Best Regards
Make sure you switched the status variable on. Alternatively, hide the cohesive elements using the view manager if you'd like.
I checked and I'm sure status is on but again I have this problem and cohesive elements didn't remove I don't know what should I do , Is it possible for me to send this file to you to have a quick look on it? !!
because is necessary for me !!
thanks
Was anyone able to solve this error?
I tried everything suggested here, but I am still getting the error.
If someone can help, it would be awesome.
See my newest comment
Would you be able to assist me? Thank you.
Hello thanks for the video, has been very useful. I chose to show the status in the outputfield and although my two surface come apart the cohesive element stand there without moving.
Another strange thing is that there's no stress in them, also for the ones that are still attached at the bottom and the top part. What do you think?
Thank you in advance
Hey Landoflemon, (I'm a Gatech Grad student)
I wanted to model a slope stability problem using abaqus, do you have some sort of tutorial for that ?
As you mentioned in the video, there are other methods to create cohesive element, could you please make more tutorials about this topic?
Thank you very much for your video. would you like to make a video to simulate hydraulic fracture(cohesive element)?
Why not just define them as a contact surface and prescribe material properties then?
Hi,
First of all, congratulations for the video. Very helpful! However, I can’t assign the section to the cohesive element. I created this section, but when I go to assign it, it doesn’t available to choose. I use continuum shell and the cohesive element has dimensions of 400 x 0.001 and a thickness of 72.
Can you help me somehow?
I found where is the error. For BC-1 and BC-2 ,apply it in initial step rather than step-1 and for BC-3, apply it in step-1. Take maximum increment as 100 and initial as 0.05. Best of luck to all.
Applying the boundary conditions in initial or step-1 makes no difference.
Great THX!!!
Thanks
very bad sound on flute.
Hi，thanks for your video.
I have followed what you have done but in the end my elements are not been deleted .
Could you tell me your e-mail address so that i can send my odb file to you and then you can tell me where it went wrong?