Abaqus - Science topic

Soohwan Jeong anwer to your querry is in this demonstration, please have a look: https://www.youtube.com/watch?v=qwYZN0rDrDI

could you please tell me how to solve it?

Veeturi Varun

thankyou so much for your replies. I really appreciate that.

which analysis is better push over or dynamic explicit? i have tried both but dynamic explicit gets aborted due to the error " constraints and connectors are not allowed at nodes with anisotropic mass" when i havent put any constraints/connectors?

To get better simulation results, stress strain behaviour of material should be same as tested in the lab. Standard material models will lead to large variation in results. With your input for 'yield stress-plastic strain data', is it containing strain-hardening beyound yield ? That should be given as input from physical tests of the same materisl used for 3 point bending.

Second issue: 3 point bending is used for solid sections, where worst effects, say maximum bending with large shear force at the loading point occurs. This test may not give good results for hollow box section. Are you following any ASTM or other test method (as recommended) ?

Parham Pourzeynali, if i am not mistaken and have got the information correct from your querry, here is the geometry that i did it with scripting. Please download it to confirm. Let me know on my WhatsApp if it helped. Good luck!

Long Le, there are two ways to control pressure with amplitude in Abaqus:

Important Note: The amplitude value itself should be between 0 and 1 (inclusive). A value greater than 1 will result in a pressure exceeding 1 MPa because Abaqus calculates the final pressure as: time x amplitude x pressure. If you still are facing issues in your project, feel free to reach me out on https://wa.me/+923440907874 for free guidance. Share your problem with me in screenshots on my WhatsApp and i will try to guide you properly. Good luck!

Switch to specialized application "Fe-Safe" which comes with bundle of Simulia Abaqus software.

For Fatigue Analysis I would rather recommend to use Fe-Safe (an specialized Application for Fracture and Fatigue which comes in bundle of Simulia Abaqus software itself).

To some extent, Yes !

For the goemetry export/import igs or step is a good format. You can easiky make an export from tekla and ten import it to abaqus.

Anton Kienast Can you share your Abaqus model (.inp)?

Mo Dj Can you share your Abaqus model (.inp)?

Musfick Alam

If you got it from the Compressometer results attached to your cylinders, it is probably correct. I thought you were trying to verify someone else's article.

Integrating UMAT and UMATHT in Abaqus for coupled thermomechanical analysis can indeed be challenging, but here are some steps and concepts that should help you structure your subroutine:

some times this is due to insufficient availabe disk space.

Maxim Naumov What do you mean when you say grid settings?

My mesh is finer than that of the paper. The number of elements in my model is about 3 times that of the paper. I used C3D8R elements only.

Seyeon Joo You will find your example in the permas4edu GitHub repository. See

Hi, you can check the reaction forces in each loading (tensile and compression), then, divide them to the area of section.

Martijn Jannink thank you for your advice:)

In this case the tribotest is performed at prescribed level of pressure

Hi,

What properties have you used for the Yarn ?

Is it Transversely isotropic or Isotropic ?

If you have any literature reference can you please post or send to me ?

I know it's been a long time since you asked and you've probably solved the problem. But I'm experiencing a similar problem and have the same difficulty.

It seems that in your code you are using global arrays when referring to pointers, as in.

pt21 = SMAFloatArrayCreate(21,101,0.0)

Although they are global in the sense that all threads have access to them, they do not guarantee thread safety. From what I read in the documentation, you would need to use mutex to lock the threads (losing performance).

Or simply define it as a local array (in the sense that it's local to a thread and doesn't need any locking for access, therefore thread-safe). Something like this:

pt21 = SMALocalFloatArrayCreate(21,101,0.0)

And they return with

... = SMALocalIntArrayAccess(ID)

If you managed to solve the problem, please give me feedback on how you did it. I'm facing the same problem and I can't compile my subroutines on demand.

Anyone have an idea how to solve?

Thank you for your answer Do you not have a solution to this problem that the temperature of the particles should decrease after welding?

Hi Engr. Tufail, thank you for your response. All three parts of my assembly were defined as separate parts when running topology optimization on my assembly and they were still merged, showing only 1 part. Also, the job is set up so that it doesn't affect the areas where these 3 parts intersect. Do you have any suggestions? Thanks again!

Eldrin a Ca, at the end of this playlist (link: https://www.youtube.com/playlist?list=PLJnI4AlLzRgzn7jXdqz8vp12k--9eDbx4) i discuss how to interpret various kind of results in ABAQUS with outputs as per the ABAQUS documentation. PLease watch to learn how to interpret results. You can ask me on my WhatsApp as well: Https://wa.me/+923440907874.

Here is a blog I wrote for guys like you. The latest updates and features needed to convert units in Abaqus and tips you must know as a simulation engineer.

To address the minimal deformation issue in your plate damper model in Abaqus:

To address convergence issues in Abaqus/Standard with Nlgeom = ON, consider using Abaqus/Explicit solver for simulations with periodic boundary conditions (PBCs). However, implementing PBCs in Abaqus/Explicit may lead to large implicit systems of equations, affecting performance. Adjusting contact settings, reducing explicit time increments, and exploring alternative constraint equations can help improve convergence. Simplifying or refining the model and seeking expert advice are additional steps to consider for effective PBC implementation in Abaqus/Explicit.

General guidelines for troubleshooting simulation issues in Abaqus software include:

I need help with this too

IT HAS TO BE COMPARED WITH THE NODE 1

FOR GOOD ANALYSIS

I would suggest approaching Mahmoud Mostafavi he might be interested to add to this discussion. I hope your research is rewarding.

Hello Akanksha,

The problem comes from using common blocks while running a process on multiple cores. The VUHARD subroutine is accessed simultaneously from every core and potentially modifies the values inside the common block. If that is the case, then you are dealing with a thread-safety problem, every thread (core) is accessing the memory address of the common block in any arbitrary order, and potentially overwriting data.

The bad news is that your current implementation may only work on a single core.

The good news is that there are ways to solve it. Depending on what you do in the subroutines, you can take advantage of Mutex (https://help.3ds.com/2023/English/DSSIMULIA_Established/SIMACAESUBRefMap/simasub-c-getthreadid.htm?contextscope=all&id=bdf77f26fbe649278cd8d1a552c63ad5) or allocatable arrays that are thread-safe (https://help.3ds.com/2023/English/DSSIMULIA_Established/SIMACAESUBRefMap/simasub-c-localarrays.htm?contextscope=all&id=30c56e1ae1e7473fadc858b5499b8e48).

I hope you find it useful!

Best regards,

Miguel

Here's a breakdown on linking Abaqus 2022 with Intel oneAPI Fortran Compiler and Visual Studio:

There are two main methods:

Engr. Tufail Thank you for the suggestion.

Any one please help to model cavitation in the abaqus software between steel and rubber materials?

For viscous step, you cannot use static solver. You will need to use dynamic step.

Thank you for your precious advice.

Can you share the UHPC CDP sheet or any reference that helps me to deal with this problem..?

No, there is no need for any other software to read the odb file. In simulating metallic foam materials in Abaqus, the choice between Crushable Foam Hardening and plastic strain with yield stress for hardening depends on the specific requirements of your simulation. Crushable Foam Hardening is used to model the behavior of compressible foam materials, while plastic strain and yield stress are more general parameters for hardening. In 2D cases, both approaches can be applicable, with Crushable Foam providing a more specialized model for foam materials. Ultimate tensile stress is crucial for failure criteria and can be used to assess material failure.

Shiyao Lin as per my understanding, shell elements primarily capture in-plane stresses (membrane behavior) and bending moments. Initial stress definitions in ABAQUS are typically for normal and shear stresses. Directly applying these to shells might not translate well to the bending behavior that shells are often designed for. I am not sure, let's wait for the expert reviews further.

S . Hamed Ebrahimi thank you, I will try

Jiaqi Wang Were you able to solve the problem? If you share your input file (both before and after restart), maybe I can find something wrong there.

I recently tested SDVs in restart analysis for coupled temperature displacement procedure and it worked fine.

Hi Ali,

If you use one of the constitutive models built in Abaqus, you can try to increase the viscosity parameters or use some scale factor to reduce the time step. If you are using a VUMAT, this should be checked in more detail.

Best Regards,

Ahmad

To verify low cyclic fatigue in a bar under cyclic load and understand the difference in fracture strain between uniaxial and cyclic loading, it is essential to consider the experimental data.

If you are using 6.14-5 ABAQUS, then send me your file on Https://wa.me/+923440907874. Beside, in the syntax the displacement is missing in field output. It should be like this:

*Output, field

*Element Output, directions=YES

DAMAGEC, DAMAGET, LE, PE, PEEQ, S, U

*Output, history,

*Node Output, nset=DeslU2m

U2,

*Node Output, nset=RFsuporte

RF2,

Beside can you also mention at which location this DeslU2m is?

Your explicit simulation will give you the dynamic response. If you simulate a quasi-static process in a severly reduced time(and thus a much higher loading rate), it's quite possible that you delay or prevent buckling phenomena.

I'd recommend running the simulation with a linear elastic material and check if you will eventually see some buckling. If nothing happens, try to apply the load more slowly (or reduce the mass scaling, if you used that).

The disk space is not enough to handle it.

Engr. Tufail I have a similar question，the Abaqus.dat file mentioned “ERROR: SIM database file cannot be opened - System Error CreateFile: code1023 ”

How could I solve the error？

Kind regards

Andy

Proches Mkawe

Hi,

I need to model two dimensional FGMs.

I define field 1 as the first coord, and filed 2 as the second coord

In state 1 , I should write the expression that grades the material property simultaneously in two directions.

In abaqus material assignment, I add two filed variables. However , I should add the material property at each position. But I don't know how to choose these points.

I can handle it in one dimensional gradation.

I wish you could provide any assistance.

there is a simple way to handle this, you can keep your module be an individual file, and then use `include 'model_file.f90'` before your umat definition.

Hello,

I have also faced with this error.

please send me a message if you have any solution to solve it

To perform uncertainty quantification using the Monte Carlo Method in Abaqus with Python, you can follow these general steps:

Here are some specific recommendations to get started:

By following these steps and leveraging Python scripting capabilities in Abaqus, you can perform uncertainty quantification using the Monte Carlo Method for your laminate structure analysis.

Please follow me if it's helpful. All the very best. Regards, Safiul

Hello again,

When your part is defined as a shell, the thickness direction should be correct, and the stacking sequence aligns along the thickness. What I meant by the viewports not being linked is that the coordinate systems of each viewport are not directly related. It doesn't matter if you actually linked them in the viewport options. Essentially, even though both viewports may display "1, 2, 3" axes, it's essential to understand that on the left viewport, it refers to the GLOBAL 1, 2, and 3 directions. On the other hand, on the right viewport, it denotes the LOCAL 1, 2, and 3 directions, defined according to your composite layup. In this context, 1 represents the longitudinal direction, 3 denotes the stacking direction, and 2 signifies the cross-product of both directions. This setup is consistent across all composite layups when using the query function in Abaqus CAE.

In most recent versions, ABAQUS CAE now actually have as global axes x,y and z and for the local material coordinate system it uses, the 1,2 and 3 directions, maybe to avoid confusions between the local and global coordinate systems. You can find on the attachments of this answer a picture of it. How you relate the local and the global coordinate system is defined in the Composite Layup section where you have several options.

At any case, for your purposes, if your part is a shell, the stacking and thickness direction should be the same automatically. However, since you are using a continuum shell section, that means that your part is actually a 3D solid part and not a shell. So you should be be careful and precise when you ask for help. In a continuum shell, you discretize an entire 3D body part. For this case, as I said in my previous answer, making sure that your Stacking Direction is on the "Element direction 2" and the rotation axis is around "Axis 2" is crucial. Perhaps you have those options on the advanced tab on your window. At any case, I attached a screenshot of how you define it in my version (2022).

Hope it helps!

Hi Babak

Can you tell me how you created "history variables" in UMAT? I assign my hsitory value to a "statev" in UMAT but ABAQUS outputs it as a "Field Output" and not a "History Output".

Thanks

Dushyanth Rudra Mahesh Velugubantla ,

the most common way to do this is to add an integer flag in the props array with the value of 1 if the element belongs to the specific part, and 0 if it does not. Then, in a global variable (where you have access for all elements) you can have another integer, where it starts with value of 0, and becomes 1 when the first element of the part has strain exceeding some value. Finally, for every element in the umat that belongs to this part, if the global variable is 1, you can delete it manually.

Dear Ganesh Jaiswal,

I think that you just need to divide your fem analysis into several explicit steps. Then, you just have to applie to these steps the mass scaling parameters you need (by choosing a critical time step for example).

Regards,

Nils Audry

Use then built in Johnson-Cook constative model for the steel (you will need parameters for the specific steel your modeling i,e, 4340 Rc ? ect.).

You can, however the simulation will be too slow in term of convergence.

You command line should be (name='TopB', side1Faces=faces)

Abaqus is a powerful Finite Element Analysis (FEA) software widely used in structural engineering analysis. It offers versatile applications, including stress analysis, heat transfer, mass diffusion, acoustics, piezoelectricity, and more, either independently or coupled with stress analyses. Abaqus has an extensive library of material models, allowing simulation of stress and deformation in various materials like metals, rubber, polymers, and more. The software's modularity and flexibility enable users to model any physically reasonable combination of elements, materials, procedures, and loading sequences. The simulation process in Abaqus involves three stages: pre-processing or modeling, processing or finite element analysis, and post-processing for generating reports or animations from the output file. There are specialized courses available for learning Abaqus software specifically designed for students with no prior FEA software knowledge. These courses cover key concepts like defining material properties, geometry assembly, meshing, and finite element analysis using Abaqus. Abaqus is crucial in civil engineering for structural analysis in areas such as highways, bridges, and other infrastructure projects to ensure the design of safe structures. The software offers advanced linear and non-linear analysis capabilities, multiphysics simulations, complex material modeling (rubber, thermoplastics), high-performance computing for reduced analysis time, contact modeling, and more.

@Alireza Akbari

Did you get any solution after that?

have you found the solution of it

Diana Hellinger, To adjust the interaction properties between the segmental linings of your packers to simulate the behavior of recycled plastic material, you can modify the friction coefficients of the contact surfaces. Since recycled plastic typically exhibits a slightly softer and less elastic behavior compared to virgin plastic, you can reduce the friction coefficients to mimic this characteristic. Additionally, you can adjust the stiffness and damping properties of the segmental linings to better match the material's response to external forces. By fine-tuning these properties, you can achieve similar results without adding an extra part between the segmental linings. For more, connect with me on https://wa.me/+923440907874

Yes, you can use the difflux subroutine to address the high temperature issue of the part and examine temperature variations over time and at different locations within the component.

To apply the convection coefficient for the SPH model of the part in Abaqus, it is advisable to consult reputable websites and available tutorials on this subject to avoid any potential mistakes.

I will give you the address of one of the reliable sites in this field:

Md Tareq Hassan, when using Finite Element Analysis (FEA), there are rules about what results you can get. It's important to make sure the results make sense and that you're looking at the right things. For example, you can't find certain forces in places unless they are fixed or pinned in a specific way. For more connect with me on https://wa.me/+923440907874