November 17, 2023 at 9:44 amElena MaierSubscriber
my problem is the following:
my model contains a plate and on top of this plate is a smaller plate (cover plate) welded. Also there is a crack in the beginning of the weld, as you can see:
The following boundary conditions are set;
- the welds (triangle volume bodys) and the bottom plate are one Part with a shared topology, since through the welding process they are one piece and that´s how the mesh gets continoous.
- the cover plate (upper plate) is bonded to the welds with an MPC, since they are also connected through the welding. The contact between the cover plate and the bottom plate is defined through friction (coefficient:0,2) because they are not bonded or something.
- the back is fixed and on the left side is a tension with 100 MPa (or a pressure with -100 MPa)
- on the weld toe is a semi elliptical crack which I inserted with the fracture Tool over semi elliptical crack, see also below:
My problem is: I do a parameter study and sometimes the crack meshs with the surrounding mesh and sometimes not. I assume it is because it is difficult because it is so close to the weld toe.
1. Is there a way to get a stable meshing for all crack sizes?
2. My simulation takes very long with an element size of 2, is there a way to get it faster?
3. how close can I go to the weld toe? right now my closest is 0,3 mm (with a hexaeder mesh and a largest profile radius of 0,2mm )
Thank you so much for your time and help.
November 17, 2023 at 1:59 pmSascha HellAnsys Employee
Generally, please note that among the Fracture Meshing tools the Semi-elliptical Crack feature has more limitations than the Arbitrary Crack feature. E.g. the Semi-elliptical Crack feature can only be applied to one surface/face and only remeshes there. That will make it difficult to achieve a crack mesh close to the border of a face.
The Arbitrary Crack feature on the other hand can cross faces as long as they belong to the same body. That might help you in achieving an appropriate mesh more often.
Note that the Fracture Meshing tools are intended for cracks within a bulk material where SIF results are actually valid (they are not in material interfaces). For interface cracking/debonding applications, you could use CZM or VCCT (https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v232/en/wb_sim/ds_geo_delam_debond.html).
I hope this information will help you.
November 17, 2023 at 4:09 pmElena MaierSubscriber
thank you so much. I can´t open the links, that doesn´t work.
I got that a little to late, I am already really far in my validation process and it is difficult to do it now with a total different crack type. Because in the beginning I thougt it could work with that crack.
Is the rest of my meshing/ contact definition realistic/good like that?
And do you have an idea how I can mesh this, to get still ok results?
It would help me a lot, thanks for your answer in advance,
November 20, 2023 at 8:35 amSascha HellAnsys Employee
the links are links to the Ansys Help. Don't you have access to the Ansys Help?
Unfortunately, I cannot comment on your engineering approach, so I cannot help you in deciding whether your meshing/contact definition is appropriate. Hopefully, someone else can comment on that.
What I can say is: If you want to reliably get a mesh using the Semi-Elliptical Crack feature, you should stay well away from the surface/face boundaries (that includes any contact and shared topology definitions). The same is true to get appropriate results for your contour integral evaluation. For the latter, the solver will help you by throwing a warning if there could be a potential issue.
Best regards and good luck for your application,
November 20, 2023 at 3:13 pmElena MaierSubscriber
Ok, thank you, no unfortunately that doesn´t work for me, because my institution is really big and they can´t give me the license number which it seems I need to get to ansyshelp.
Ok thank you for the information.
My colleague is working with the arbitraty crack, and it seems less stable than the semi elliptical crack. thats why I chose that one, and in the beginning I was distant from the other body, but now I have to model the crack closer.
- You must be logged in to reply to this topic.
Boost Ansys Fluent Simulations with AWS
Computational Fluid Dynamics (CFD) helps engineers design products in which the flow of fluid components is a significant challenge. These different use cases often require large complex models to solve on a traditional workstation. Click here to join this event to learn how to leverage Ansys Fluids on the cloud, thanks to Ansys Gateway powered by AWS.
Earth Rescue – An Ansys Online Series
The climate crisis is here. But so is the human ingenuity to fight it. Earth Rescue reveals what visionary companies are doing today to engineer radical new ideas in the fight against climate change. Click here to watch the first episode.
Subscribe to the Ansys Blog to get great new content about the power of simulation delivered right to your email on a weekly basis. With content from Ansys experts, partners and customers you will learn about product development advances, thought leadership and trends and tips to better use Ansys tools. Sign up here.
- Saving & sharing of Working project files in .wbpz format
- Solver Pivot Warning in Beam Element Model
- Understanding Force Convergence Solution Output
- An Unknown error occurred during solution. Check the Solver Output…..
- What is the difference between bonded contact region and fixed joint
- The solver engine was unable to converge on a solution for the nonlinear problem as constrained.
- whether have the difference between using contact and target bodies
- Defining rigid body and contact
- Colors and Mesh Display
- A solver pivot warning or error has been detected
© 2023 Copyright ANSYS, Inc. All rights reserved.