r/Abaqus

Hey everyone,

I still see so many of us manually calculating true stress and strain in Excel, dragging formulas down 16,000 rows, and trying to manually snip out the descending plastic points after necking just so the solver doesn't throw a convergence error.

It’s a massive waste of time and leaves too much room for copy-paste errors.

Abaqus actually has a Calibration tool that handles all of this automatically, but it feels like nobody uses it.

Here is the faster workflow:

1. Go to Model -> Calibration -> Create
2. Paste your raw engineering data (Data Set).
3. Right-click the data set -> Process -> Convert. (This automatically switches nominal to true form).
4. Create a Behavior (Elastoplastic Isotropic) and map your data directly to your material.

The best part is you can easily pinpoint the yield point and calculate the ultimate tensile strength right in the UI.

-Abaqus still requires your plastic stress data to be in ascending order. You still need to manually delete the decreasing values after necking, otherwise your simulation will fail.

I actually just re-edited and uploaded a quick visual walkthrough of this exact process on my channel if you want to see the step-by-step UI clicks:http://www.youtube.com/@FEAMASTER?sub\_confirmation=1

https://preview.redd.it/euruwuhkbzxg1.png?width=2750&format=png&auto=webp&s=21d8f8d3daf49e607b27bd1c4b79513259b574e4

Hello everybody,

I have a problem when I try to run a modal analysis (frequency step with 10 eigenvalues) of my model in the Abaqus. I get the following error message: "Three factorizations in a row failed. Check the model. It is possible that the model contains the kinematic coupling definition set up in a way that a degree of freedom has neither mass nor stiffness".

Does anybody already had that same problem or knows why this is happening?

Thanks

Hello guys, hope you are doing well!

I´m new to Abacus (only started using it today) and I need help finishing this FEM simulation.
I´ve seen some tutorials on how to use this programme and search online but I cannot find how to fix this error that is showing up. I´ve seeded this part as you can see in the second print, but I´m not able to mesh since this is happening (error on the first print):
If you could help me I would highly appreciate since I have to finish and submit this assingment as fast as possible.
Thanks in advance!

https://preview.redd.it/jvrnjlcrifxg1.png?width=1919&format=png&auto=webp&s=2281e24fecac096ac967979b2f3f9e741b94ec1a

https://preview.redd.it/3qeexg4lifxg1.png?width=1919&format=png&auto=webp&s=e64fb4dfb80b987dec1c5d83677128252e7997b5

Was trying to find deformation in a membrane with S4T elements with pressure as load and temperature change from BC and predefined fields. Given energy stabilization of 0.0002 but the model is always very slow, I am not sure if it is suppose to take an hour for just a rectangle to deform
It is now stuck here for an hour at 0.09..
Any help is appreciated to solve these type of problems

https://preview.redd.it/obvfbuvtc5xg1.png?width=1024&format=png&auto=webp&s=340f9e04f6974f6ecee91227c18e0b4da22c17cc

Hello everybody,

I have a problem when I try to run a modal analysis (frequency step with 10 eigenvalues) of my model in the Abaqus. I get the following error message: "Three factorizations in a row failed. Check the model. It is possible that the model contains the kinematic coupling definition set up in a way that a degree of freedom has neither mass nor stiffness".

Does anybody already had that same problem or knows why this is happening?

Thanks

Hey all, so running a static general step (model 1) to apply a simple bolt loading to create an initial condition ranging from 4000N-7000N, all of which run just fine. When importing these various loading results into a dynamic explicit model (model 2) as its initial state, the lower loading imports, package and run just fine, however finding that at loadings of 6000N-7000N the explicit packager silently aborts, and all I get is the standard check error message if exist. I have reviewed all files associated with the failed job and none of them list errors, so basically fully blind to what Abaqus is choking on. I have gone back and evaluated plastic strain, stress concentrations, mesh size and regime, onset of damage and damage evolution, etc, and no glaring issues, no excessively distorted elements, no overclosure that I can find, no super high plastic deformation (slightly plastic but on the order of milli strain-micro strain), and no damage initiation. At this point beating my head against the wall on why this is aborting. Anyhow that is a 10,000 foot overview, so if anyone has had similar issues and found a fix, or any suggestions, I would be super appreciative!

Hi everyone,

I’m currently working on a project where I need to design and analyze an aircraft fuselage section using ANSYS, and I’d like to integrate Python (PyAnsys) into the workflow.

I’m still a beginner with PyAnsys, so I’m looking for guidance on how to get started properly — especially:

• Setting up geometry and meshing with scripts
• Running structural analysis using Python
• Best practices or tutorials for aerospace applications

If anyone has experience with this or can share resources, example scripts, or advice, I’d really appreciate it.

Thanks in advance! 🙏

https://preview.redd.it/x110eibgtbxg1.png?width=960&format=png&auto=webp&s=2ad9cbe424304d7a4627cff824fcfe23c2f224f0

Just taking a moment to say I love Abaqus. I’ve used, extended , automated for almost 20 years. Used to work there too!

I am doing a project at work that requires LS-Dyna. Great code. Innovative for sure. But abaqus is just so darn easy to use. I love it.

In my current work, I am trying to integrate the “Cyclic Jump Technique” as introduced back then in 2006 from Cojocaru by modifying my UEL Subroutine.

The methodology is as following.

• An initial simulation for 6 cycles is executed.  
• Then I extract from the ".odb" at last frame [end] the Displacements and Internal Variables.  
• Thereafter the second simulation is initiated, where it contains two Loading Steps. In the first step the Extracted Displacement is applied as displacement control load case and at the last increment of the first step the extracted State Variables are imposed.  
• This allowed me that the second Loading step of the second simulation has as an Initial State the predefined extracted Displacements and Internal Variables.

 

The issue now arises at the very first incremental step (KINC=1) for the second loading step of the second simulation.

Even though the original simulation faces no converges issues, when I use the transfer data approach for some reason Abaqus in the second simulation in order to converge sets the original displacments that I imposed back to zero, as you can see on the image on left side (more Images in the attachment as a .zip file), with no load transfer within the elements hence lack of continuity.

Have you ever occured such a similar case within Abaqus Framework?

Second Simulation - Second Loading Step - New Fatigue Cycles: 

KINC = 0, t = 0.0 [sec]

https://preview.redd.it/p9ehq8ho14xg1.png?width=1445&format=png&auto=webp&s=ed0668fce250a8bc02d1e1bfdc4a8cc422b9f7b5

https://preview.redd.it/8prokjqp14xg1.png?width=1449&format=png&auto=webp&s=356dc2d1d1c5183632449847335ab5a6684cfda1

KINC = 1, t = 0.025 [sec]

https://preview.redd.it/8aef3ohmv3xg1.png?width=1451&format=png&auto=webp&s=a30d4240526d4efe07d30cc4bd3387e8dfdf2297

https://preview.redd.it/l2onfd9s14xg1.png?width=1327&format=png&auto=webp&s=2a28b5f88d74289039c9b719a52c6c34ac5d7280

Hi, I submitted the optimization 5h ago, and it hasn't started yet. No one else is running anything else, and I am running it without multiple processors, so I should have enough tokens.

Am I missing something?

https://preview.redd.it/2la5kgwvrzxg1.png?width=478&format=png&auto=webp&s=190118d81897366bbc9657ddb6d5795d596f4171

Hi, I am trying to run a topology optimization on an imported mesh (implant over bone with screws)

I normally import all meshes as volume meshes. But when I try to freeze the regions for the optimization, I can not select the surfaces I want to freeze. Is there a way of solving these that is not manually selecting every element that is part of the set?

A solution I was exploring was to also import the object's surface mesh, as it creates the sets for freezing. The problem with this solution is that I then get an error saying that some parts have elements without any section assigned.

Is there an appropriate method to select the areas for the freezing constraint?

Thanks in advance

I have a thermal structural step defined. Th material is also well defined, however I have the error message "At least one CAE model with valid thermal/structural step should be defined before creating the AM Model" when I try to Create AM Model.

Please help me, I can't find what is wrong with my model. A example.inp example file would be appeciated. Thanks in advance.

Hi, I’m modeling a CFST member in Abaqus under bending. I used surface-to-surface contact between the inner steel tube and the outer concrete core. For the interface, I used hard contact in the normal direction and penalty friction in the tangential direction with a friction coefficient of 0.4, with separation allowed. In this case, the model gave about 200 kN peak load.

Then I replaced the concrete with steel properties as a sensitivity test, and the peak load still stayed around 200 kN, although the response curve was slightly different. But when I tied the core to the steel tube using tie constraints, the concrete-core model increased only slightly, while the steel-core model jumped to about 450 kN.

Does this mean the contact model is not engaging the core properly? What am I doing wrong, and how should the concrete-steel composite behavior in a CFST be modeled correctly?

Thanks!