Composite Fatigue Abaqus Simulation with Subroutine
In this package, we try to teach you step-by-step, from the theory of the problem to the final results of the simulation on composite fatigue specimens. As you know, to perform this analysis using Abaqus software, we need to use UMAT subroutine writing. To get familiarity with this subroutine, you can purchase the subroutine training package of UMAT and VUMAT through our website. This training package helps you to perform the analysis easily you need in the field of Composite Fatigue Abaqus. Consequently, the following is a detailed description of this workshop. Composite fatigue Abaqus is presented here in this training package.
Introduction to Composite fatigue
Fatigue life is defined as the loading cycle’s number (stress) of a specified character. That is a specimen sustains before happening any kind of failure. We can determine the composite fatigue life by the strain, stress, or energy approach. Due to the increasing growth of science and industry, there is a need to develop advanced materials with more profits. Composite materials, due to higher efficiency and economic benefits, have become a suitable alternative to traditional materials in various industries. Therefore the development of these materials by understanding how to produce and study their properties. How to calculate the final life of fatigue for them is essential. Follow this description to understand the Composite Fatigue Abaqus capabilities and features.
Workshop 1 part 1: Theory
In the first part of this workshop, we first mention the importance of material fatigue. To check for fatigue in composite materials, you need to know how to write subroutines. In the following, we will introduce how subroutine works. The theory that governs this subroutine writing is the theory of “Shokrieh”(for more information, you can refer to this article).
The equations in this theory are based on the “Hashin” criterion. We explained it in this package’s part. In this theory, we have dealt with how to calculate the final
composite Fatigue Life in three dimensions based on the loading cycle’s number.
Workshop 1 part 2: Subroutine writing
In this part, we have presented how to write subroutine UMAT in Fortran language based on the flowchart provided in the initial part to calculate the amount of fatigue and final composite fatigue life (Composite fatigue Umat).
Firstly, the loading method in this example is periodic and based on the number of loading cycles. We calculate the reduction of properties and their effects on the model’s life. In addition, how to define the parameters, define the initial values, and writing the relationships in Fortran code we completely taught.
Due to the fact that composite materials consist of matrix and fiber, similar conditions have been studied separately for fatigue in both material’s parts. You can watch the demo video to understand more about composite fatigue Umat applied in this training package.
Workshop 1 part 3: Implement modelling in Abaqus software
In the last part, we will go to the Abaqus software and explain how to implement the written subroutine on the model designed in the software. The required settings for each module are trained. Finally, this subroutine will be able to display the final composite fatigue life, behavior of the material, including the reduction of elastic properties, strengths along with other parameters such as stress, strain, displacement, fatigue failure criteria in different modes as output. The written subroutine can be used for a variety of complex to simple models.
If you are not familiar with this subroutine, you can see some information about this subroutine in ABAQUS documentation. However, you can get advanced teaching about these types of subroutines by purchasing these two packages “UMAT Subroutine (VUMAT Subroutine) introduction” and Advanced UMAT subroutine(VUMAT subroutine) in ABAQUS package.
If you are working on composites and need some resources about composite FEM simulation click on the composite analysis page to get more than 20 hours of video training packages of composite materials simulation.
In comparison to metals, composites’ damage mechanisms are less well known. Composite materials and structures are susceptible to defects, whether they appear during material processing, component fabrication, or in-service use. Understanding how the damage or defect affects the structural integrity of the composite component is crucial to determining how critical the defect is. If we can somehow determine these damages and tend to them in time, the maintenance cost would be severely decreased. Also, our design will be better and well-optimized.
It’s true that the composite structures have sufficient strength and stiffness but like other structures, they may get damaged during the service. The damages could be caused by impact, low resistance to the service environment, overloading, Staff carelessness, etc.
In-service damages include:
- Impact damage
- Fatigue
- Cracks
- Delamination
- Fiber fracturing
- …
Service flaws in composite structures are typically caused by impact damages. Delamination is the most frequent impact-related damage. Delamination occurs when layers in a laminated composite are split, creating a mica-like structure with a considerable loss in mechanical properties. Delamination is the separation of the laminate at the boundary between two layers as a result of shock, impact, or repeated cyclic pressures. Individual fibers can pull away from the matrix, for instance.
It is the engineer’s duty to analyze the structures and determine the defects and damages so that the structure can keep working properly and lower the cost of maintenance. With the help of Computer-aided engineering (CAE) and finite element method (FEM), you would be able to do this task in the best way possible.
We are here at the CAE Assistant to explain some about composite material damage and introduce some FEM tools to simulate these damages correctly. Also, we will help you out learn how to simulate and analyze your model and structure. With our high-quality education, you can learn how to work with the Abaqus and analyze composite structures. I recommend you read the topics of this training package on the right side of this page and if you have more questions about this package and its content and quality, ask on the live chat on the left side of this page.
Read More: All about fatigue composite
Users ask these questions
In social media, users asked questions regarding fatigue analysis, cyclic loading, composite fatigue, etc. We answered some of them, which you can see below.
I. Long cycle simulation with the ABAQUS
Q: Can we use Abaqus directly to run a long cycle simulation similar to an experiment, or do we need to add a subroutine?
A: Hello,
Depending on your material and formulation for the cycling, you need to use UMAT or USDFLD subroutine to do such a simulation. I can recommend you some tutorial videos for now:
https://www.youtube.com/watch?v=96sfwnvLHkA
https://www.youtube.com/watch?v=Go8entmePiQ
Simulation of Fatigue in Abaqus
Composite Fatigue Simulation with UMAT Subroutine in ABAQUS (unidirectional)
II. Fatigue analysis with UMAT
Q: Hello Abaqus users,
I’m writing UMAT for fatigue analysis. I use direct cyclic step for calculations. My properties depend on N cycles or total time. Do you know how to define the total time step or a number of cycles in UMAT?
Now, I calculate the total time by KINC parameter (increment number). It works fine until my results converge. If not, the total time reset to zero, but the increment number does not. I tried to call TIME(1) and TIME(2), but they just show step time, not the total time.
Abaqus experts, how to address this problem?
A: Hi,
I didn’t understand your question. However, when you want to use a subroutine to simulate fatigue in the composite structures, you define steps, and for each step, you define a specified number of cycles. Then, you can observe the effects of fatigue on material properties in each step.
I recommend checking the link below. You will learn many things about implementing subroutines to simulate composite fatigue.
Composite Fatigue Simulation with UMAT Subroutine in ABAQUS (unidirectional)
Best regards.
III. Fatigue and the number of increments
Q: How to increase the number of step increments in the ABAQUS standard?
The problem is that the ABAQUS has a limit number of 10e7 (one billion) for the number of time increments. Is any way to use more than one billion?
I need it for fatigue analysis.
Thank you.
A: Hi,
I don’t know what method you used for fatigue simulation. However, you can create multiple steps and divide the increments between the steps.
Check the link below. You might find something useful in it.
Simulation of Fatigue in Abaqus
Another recommendation is to write a subroutine (UMAT or VUMAT). You can define the number of cycles you need, define several increments, and assign the cycles to the increments. For example, you have 100 million cycles; then, define 100 increments and assign every 1 million cycles to one increment.
Something like this is done on a composite model in the package that I sent you its link:
Composite Fatigue Simulation with UMAT Subroutine in ABAQUS (unidirectional)
Best wishes.
Tim Wöhler –
very good. I think a team should have made this subroutine because it was so complex.
Experts of CAE Assistant Group –
Thanks.Yes. The CAE Assistant Group wrote this subroutine as a team.
Amanda Diaz –
Hello, CAE assistant team., wonderful package, I used the context of this package for some researches in Fatigue of composite materials Field.
alex-1193 –
Hi, why there are no description for workshops or some preview or pictures of workshops?
Alder-oz –
The step-by-step approach used in this training package makes it easy to understand and follow, from the theory of the problem to the final results of the simulation on composite fatigue specimens.
Dr.Rohit –
It helped me understand some of the basics of writing UMAT subroutine for composite fatigue behaviour
Edmundo –
I’m thrilled with the accuracy and reliability of the fatigue simulations. The insights have been crucial for my analysis. Are there any upcoming updates or new features planned for the package?
Valerio –
The package delivered exactly what I needed for my composite material simulations. I’m interested in learning more about how to fine-tune parameters for specific applications. Any tips?
Albaida –
Fantastic product! The ease of use and detailed results were just what I needed. Can you provide advice on how to integrate this tool with other analysis methods or software?
Jacinta –
The fatigue simulation package has made a significant difference in my project outcomes. I’d like to know if there are any additional modules or extensions that could complement this tool?
Ciro –
Excellent tool with user-friendly documentation. I was able to implement it quickly and effectively. What’s the process for requesting support if I encounter issues with the subroutine?
Quispe –
“This package is a game-changer for my projects. The ability to accurately simulate composite fatigue is invaluable. I’m curious about any additional resources or case studies that could help enhance my understanding further.”
Claudiu –
The composite fatigue simulation package exceeded my expectations! The setup was straightforward, and the results were highly accurate. My only question is: how do I update the subroutine for future versions of Abaqus?
Ion –
Impressive performance! The integration with Abaqus was seamless, and the detailed analysis has helped me optimize my designs significantly.
Ramiro –
Great experience with the composite fatigue simulation package. The results were precise and actionable.
Quispe –
This package is a game-changer for my projects. The ability to accurately simulate composite fatigue is invaluable. I’m curious about any additional resources or case studies that could help enhance my understanding further.
Caridad –
Very satisfied with the results and the support provided. The simulations were highly accurate. How can I access more advanced training or workshops on utilizing the package effectively?