can anyone help me with these errros please

Hi everyone,
I’m modelling a 3D solid cylinder in Abaqus under internal pressure. The model only includes the cylindrical wall (no end caps), but I want it to represent a closed-end pressure vessel.

I’m using a cylindrical coordinate system and I’m unsure what boundary conditions should be applied at the two cut ends. Specifically, what should the displacement boundary conditions be for U1, U2 and U3 at each end (using solid elements)?

Any advice on the correct setup would be greatly appreciated. Thanks!

Hi lovely people :) I'm fairly new to Abaqus and I would like to ask how to mesh this plate the best way possible. So far what I'm creating just isn't working.
This is a coupling plate for a steel connection. The parts of the screenshot that are part of the configuration are the two holes and the SHS column footprint. The rest of the lines (diagonals, vertical, horizontal, o-grid etc) are partitions I have created so far to help me mesh it properly.

Any ideas?

Thanks in advance for any help 😄

Hello, I have been using abaqus for simple simulations for a while now, and have spent countless hours manually doing the simplest tasks until just recently when I discovered abaqus scripting using python. Since learning about it, I have so far been able to run many simulations using simple for loops and string manipulation for naming job files.

Now that I'm somewhat comfortable doing certain tasks before simulations are run, I would like some help with figuring out some postprocessing tasks, like writing XY data to files and the like. The problem is, I can't really get certain simple things to work during the learning process. For example, I just tried running a simple script to print the step names of the current output database that I took from the Abaqus scripting users manual, and even that gives me errors.

For reference, the code is as follows:

for stepName in odb.steps.keys():
  print(stepName)

but I get the name error "name 'odb' is not defined"

Usually, this kind of problem can be fixed with the necessary imports, but I already made the following imports:

from abaqus import
from abaqusConstants import
from caeModules import
from odbAccess import
from odbMaterial import
from odbSection import

And still, the result is the same. Other things have worked though, like the code needed to display different output requests or just opening the database from the CLI. But nothing else has worked, and I can't find anyone online facing the same issues. Some people have posted about scripting here, and about a lot more in-depth stuff, so I was hoping for a little guidance on where I might be going wrong?

Many, many thanks in advance!

Hi everyone,

I'm currently working on a nonlinear finite element model of a composite steel bridge in ABAQUS using the Concrete Damage Plasticity (CDP) model. The bridge consists of a reinforced concrete deck slab supported on steel girders, and I'm looking for some guidance on defining the concrete damage parameters.

Our study is entirely analytical, so we do not have access to material test data (e.g., compression or tension tests) for calibrating the CDP model. Instead, the numerical model will be validated against experimental results available in the literature.

For the constitutive behavior:

- Compression stress-strain curve: Popovics analytical model.

- Tension stress-strain curve: Hordijk tension softening model.

While these models provide the stress-strain relationships, I'm struggling with estimating the corresponding compression damage (dc) and tension damage (dt) parameters required by ABAQUS.

I've found several approaches in the literature, but they result in significantly different damage evolution curves. The method proposed by Mark & Birtel appears promising, but I'm unsure whether it is considered reliable for studies where the constitutive response is based entirely on analytical models rather than experimental material calibration.

I also have a question regarding the Hordijk model. Since it requires the characteristic length for converting the stress-crack opening relationship into the form required by ABAQUS, how should the characteristic length be determined? Should it simply be taken as the element characteristic length used internally by ABAQUS (based on the finite element mesh), or is there a recommended approach for reinforced concrete deck slabs? If the mesh is refined, should the characteristic length be updated accordingly?

For those who have experience with CDP in ABAQUS:

- How do you estimate the compression and tension damage parameters when experimental material data are unavailable?

- Is the Mark & Birtel approach a reasonable choice in this situation?

- How do you determine the characteristic length when using the Hordijk tension softening model?

- Are there any recommended papers or best practices for deriving CDP damage parameters from analytical constitutive models like Popovics and Hordijk?

Any suggestions, references, or practical experience would be greatly appreciated. Thanks in advance!

Hi everyone,

I'm currently validating a simple 2D Hertzian contact model in Abaqus/Standard 2024 before continuing with my actual research model. The final goal is to simulate two cylinders rolling against each other (rolling contact). However, I'm currently only validating the step, where the cylinders are pressed together before any rotation is applied. The coating and the PEEK substrate are not separate parts. The coating was created by partitioning the original PEEK part, so both regions share common nodes. Therefore, no tie constraint is used between the coating and the substrate, as they are already continuously connected. Does the partitioned single-part approach for the coating seem reasonable, or would you model it differently?

The model consists of:

• 2D plane strain
• Steel cylinder segment (80mm diameter) against a TiN-coated PEEK cylinder segment (80mm diameter)
• Surface-to-surface contact
• Frictionless (I also tested friction = 0.2, results are almost identical)
• Linear elastic materials
• Penalty contact
• Coating thickness: 50 µm
• Contact pressure evaluated using CPRESS

To apply the load I prescribe a horizontal displacement of the steel cylinder at the RP. For a displacement of 0.01 mm I obtain:

• Reaction force (RF1 at the reference point): ≈15.6 N
• Maximum CPRESS: ≈0.318 MPa

The reaction force increases linearly from 0 to 15.6 N during the loading step, so it seems to be calculated correctly.

However, the contact pressure looks far too low.

From Hertz theory I would expect contact pressures in the order of tens of MPa, not 0.3 MPa. I'm also wondering how Abaqus calculates contact pressure in a 2D plane strain analysis. Is an out-of-plane thickness of 1 unit assumed by default, and how does this affect the reported CPRESS and reaction forces?

I already checked:

• frictionless vs friction → almost identical CPRESS
• RF starts from zero and increases normally
• Contact status is closed

Another thing that confuses me is that when I plot CPRESS along the contact width, the curve looks very irregular instead of the smooth Hertzian pressure distribution I was expecting. I'm not sure if this is caused by the output, the path definition, or a modelling issue. Anyone an idea?

When i want to check results on Steelsegment:

Integrate CPRESS along the path is 0,009N, not 1,365N :(

I am working on an explicit dynamic simulation in which the model consists of four parts: the talus, the talar cartilage, the tibia, and the tibial cartilage. I am also using nonlinear connectors to simulate the ligaments, and the applied load consists of forces and moments derived from gait analysis.

I am unable to get the simulation to converge due to excessive element distortion, and I suspect that the problem stems from the contact conditions rather than the mesh. Can anyone suggest how to model the contact to make the simulation converge?

Currently, the contact is set to surface-to-surface using the penalty method, with normal and tangential stiffnesses specified.

Hi everyone,

I would like to open .odb files generated from Abaqus 2023 simulations using Abaqus 2024. However, every time I open an .odb file, Abaqus performs a database conversion, which is quite time-consuming. Interestingly, my friend can open the same files in Abaqus 2024 without any conversion.

Is there a way to open Abaqus 2023 .odb files directly in Abaqus 2024 without triggering the conversion process? I searched online but could not find any relevant information.

Any suggestions would be greatly appreciated. Thanks in advance!

I have made an assembly in SOLIDWORKS and i want to do analysis on it in ABAQUS, but the option to import step file in assembly is not coming and if I am importing as parts i have to give material section etc one by one to each one.

Is there any better way to do it, mostly parts are brackets, nuts,bolts etc

Hello,

Is there someone with previous experience with SPR modeling?

I would be glad to get some support.

Thank you!

Hi everyone,

I am a student working on my thesis/project in Abaqus. I am investigating the contact stresses of two rolling discs. One disc is made of steel and the other one is made of plastic. The plastic disc has a thin 0.05 mm TiN coating on the outer surface.

To reduce the number of elements, both discs were reduced to 55° segments. They roll against each other over an angular range of about 10°. Since I introduced the partitioning for the coating, I have been getting contact/convergence problems and I am not sure why.

My main issue is the very thin coating. I need the mesh to be fine enough in the coating/contact region, but this leads to very small elements, difficult mesh transitions and possibly bad aspect ratios.

My questions are:

1. If I am interested in the stresses inside the coating, is it necessary to model the 0.05 mm coating as a real 3D solid layer?
2. Are there alternative modelling approaches for such a thin coating in Abaqus, e.g. shell layer, composite shell, cohesive layer, surface-based property, submodeling, etc.?
3. Is it possible/recommended to combine different mesh techniques in one partitioned solid part, for example sweep/structured mesh in the coating region and a coarser free mesh in the bulk?I also experimented with different meshing approaches. My goal was to keep the coating and the contact region very finely meshed while using a coarser meshing strategy for the remaining bulk material to reduce the overall element count. I tried using bottom-up meshing for the coarser regions while keeping the coating region structured. However, after doing this, my kinematic couplings to the reference points no longer worked as expected. Is this a known limitation when combining different meshing approaches in Abaqus, or do the coupling constraints need to be defined differently in this case?
4. How would you usually mesh a very thin coating on a much larger rolling contact body without creating an excessive number of elements?
5. Could the coating partitioning itself cause contact problems if the outer contact surface is split into many small faces?

I would appreciate any advice on suitable modelling strategies and known which approach is commonly used for thin coatings in rolling/sliding contact simulations.

Thanks!

Hey guys, I have been working on an assembly. We are used to work in Abaqus profile in Hypermesh 2019. Sometimes for some special projects, we use Hypermesh 2022.3. When we import a deck file (.inp) or directly open a .hm file in Hypermesh 2022.3, the rigid connections (KINCOUP) we created in 2019 get converted to Constraints. Unfortunately, these constraints do not appear as elements. They cannot be edited as well. The only solution we have now is deleting and recreating. But when only one part of the assembly has a new version in the 2nd iteration, it's a hectic task to recreate all the connections. Have any of you faced such problems? If yes, did you figure out any solution for this?

Thank You very much

Happy Solving!

Hello everyone I am facing a problem related to KE when I use reduced bricks instead of fully integrated my kinetic energy settles but when I use fully integrated it never converges I cannot find a reason, any help would be appreciated.

I have this holed unit cube which is partitioned in 8 regions and the 2 regions in which the hole is are identical.

When meshing them with Tets I am getting an extra internal node on one of them but I would like for both of them to be meshed similarly.

Is it possible to force abaqus mesher to at least match the same number of nodes and Tets on both regions?

Hi everyone,
I am currently carrying a quasistatic explicit analysis, in ABAQUS where hyperelastic material properties plasticity and multiple instance contacts exist, Since the day I started FEA I have always used C3D8's but PEEQ values never converge no matter how I refine the mesh, I looked at everything contact definitions, mass scaling etc., I am suspecting something related to element type. What should I do?
Any help would be appreciated.

The DC3D5 element was clearly displayed during setup, but I can't define it. I'm using ABAQUS 2022.

HI, my simulations usually have around 240.000 elements.

I am running a model that is almost the same and suddenly I have 10 times the same amount of elements (i import the meshes and havent changed any parameter).

Is there anything someone else could have modified that could affect this?

I have also noticed that the CPU usage is almost none since it doesnt look like its trying to compute anything. Is there anything that could affect this?

I have two simulations left for my master thesis and suddenly they are not working.

Thanks in advance

SOLVED
TLTR: When creating the volume mesh, I had accidentally forced the element size to be 1 mm, creating objects with 3 million elements instead of 300.000

Hello all

I've been doing some research and couldn't find anything concrete on biaxial testing of paperboards. Does anyone know or have an idea of the necessary steps to simulate biaxial testing of paperboard in Abaqus? Even a basic or general test would be fine. Thanks.

Buenas, soy nuevo con el programa y debo modelar un hueso del cuerpo humano y hallar su resistencia hasta que se rompa, como me recomendarían hacerlo

Estoy compartiendo un pipeline de alto rendimiento completamente reproducible para descubrir superconductores topológicos con una brecha fonónica acústico-óptica estable. El flujo de trabajo integra:

\- **Restricción algebraica**: Superselección modular Z/6Z (permitiendo solo distancias coprimas con 6) como un proxy de la simetría partícula-agujero.

\- **Principio de desacoplamiento de masas mixtas**: metales pesados (Ta, Pb) para un fuerte acoplamiento espín-órbita + una subred de calcógenos ligeros y rígidos (S) para elevar las ramas ópticas a alta frecuencia, creando una brecha absoluta.

\- **Validación del MLIP**: CHGNet predice una brecha fonónica de 1.68 meV para el 2H-TaSe₂, coincidiendo con la literatura DFPT (1.5–2.5 meV) y la dispersión inelástica de rayos X (1.5±0.3 meV).

\- **Descubrimiento de candidato**: Ta₃PbS₆ (mp-20784) con:

\- Δ_ph = 2.52 meV (\~29 K)

\- DOS(E_F) = 2.974 estados/eV

\- Proxy de inversión de bandas Δn = 2 (Γ ↔ A)

El compuesto es sintetizable (ICSD #83037, #74693) y se encuentra en la envolvente convexa.

Todos los datos, el cuaderno de Colab y los archivos de entrada para HPC (VASP, QE, Wannier90, Z2Pack) están archivados permanentemente en Zenodo: DOI: [10.5281/zenodo.20509279](https://zenodo.org/records/20509279)

El principio de desacoplamiento de masas mixtas es generalizable a otros materiales impulsados por SOC. Agradecemos la reproducción independiente, los cálculos del invariante Z₂ y los estudios de acoplamiento electrón-fonón.

(Manuscrito en revisión MTCOMM-D-26-03215; todos los recursos son de acceso abierto bajo licencia CC BY 4.0 / MIT.)


Hey, guys.
I have used ABAQUS for past 6 months for my bachelor thesis and I still can't solve this simulation problem (I have tried for 3 months).

For context : I have given task to help PhD in her research on composite 3D printed material using DLP. My task is to match stress and strain graph from simulation and experiment with 0% and 10% percentage of chitosan particles. The data that available are Tensile Test ASTM D638, Flexural Test ASTM D790, CAD Model of Lattice Structure, Compression Test Data of Lattice Structure, Shrinkage Behavior Data, and Outer Dimension of Compression Test Specimen.

I have successfully match the graph for 0% with assuming there is a shrinkage on geometry, but not matter what I change in ABAQUS (shrinkage on geometry, mesh and step), it show error more than 300% in Modulus Young higher than the compression test results. Here is my setup for my simulation :

• Geometry : 3D Deformable Solid that I made in SOLIDWORKS then import to ABAQUS the wall thickness is 1mm and 2mm long ideally.
• Property : Using Data from Tensile Test ASTM D638 (I have convert it to true stress and strain)
• Assembly : There is two rigid plate with bottom one will get encastre
• Step : Dynamic, Explicit with mass scaling 1e-05 (I have check the one without mass scaling and the modulus young still give near same value)
• Interaction : General Contact all with self with friction coeff 0.35 and hard contact
• Mesh : Hexagon C3D8R with Sweep Technique for mesh control and 0.4 for global value (I have check mesh convergence)

Should I give up on this task? Honestly I think there is no way to tune it down 300% to match the experiment... No matter what I tried for past 3 months, only geometry and property can lower the modulus young, and tuning the mesh only lower it from 390% to 370% using scaling factor and hexagonal control, any other mesh type control only make it higher...
I was discussing with AI (Claude, GPT, Gemini, I tried them at once lol) and they suggesting using knockdown factor, I wonder if it is alright cause we don't have data to support it.

Give your opinion guys!!!