Hi Michael,

I am not sure whether I understand your question. ABAQUS surely has capability of predicting crack propagation. Particularly in ABAQUS/Explicit, element deletion technique is provided such that the element,where the failure criterion is locally reached, will be removed from the calculation. Thereby dynamic element deletion can be visualized as a crack progration.

It actually provides a variety of failure models for different materials and different problems. But for doing it correctly, you must do some benchmark tests to make sure the failure criterion that you used is reasonable. Except that, the numercial results very depend on mesh design.

I suggest you to check ABAQUS manual (ver6.5) section 11.2.8 and chapter 11.6 for details. Also in the ABAQUS/Example problems manual, problems 2.13 and 2.14 are both good examples that you should perform for being familiar with the method.

Hope this helpful for you.

Zhenyu

In addition to Zhenyu's reply, I want to add that Abaqus can handle crack using cohesive zone model. In old versions, one has to write an UEL to handle cohesive elements. In the new version (6.5), it allows the user to define the traction-separation behavior in the contact elements, so you can regard this as cohesive elements, to my understanding.

For the ad hoc problem, if you want to implement your own fracture criterion, the cohesive element can be easily implement using a template that Prof. Bower and I wrote. Please see paper #7 in http://web.utk.edu/~ygao7/publication.htm

Yanfei,

In my knowledge, cohesive zone model is very powerful for the problem where the crack path is known, such as the delamination of a bilayer (thinfilm on substrate ect.) where the crack is always propagating along the interface between two materials. While for the problem that the crack paths are too complicate to be predicted such as petalling process of a plate subjected to blast loads, the cohesive zone model cannot handle it in an efficient way.

Please correct me if I misunderstood something.

Zhenyu

Zhenyu,

 You are right about the advantages and disadvantages of cohesive zone model. To my observation, here are two major advantages:

(1) crack path is predefined

(2) the system will be artificially more compliant with the addition of cohesive elements

 The first one can be avoided by introducing cohesive elements everywhere, but for highly symmetric problem, the path will be mesh dependent. With cohesive elements everywhere, the second problem is more severe. So we need to make sure the initial response is almost rigid. But doing so will introduce snap-open instability. That's why Prof. Bower and I modified the traditional cohesive elements along this line. 

 thanks

yanfei 

Hiya,

Nice and informative discussion.

Cohesive zone modelling always have some disadvantages as discussed by Yanfei and others.

One way of removing the mesh bias is to use cohesive elements everywhere but it is a tedious job and many problems regarding stability and convergence.:)

Simulation of cup–cone fracture using the cohesive model  Engineering Fracture Mechanics, Volume 70, Issue 14, September 2003, Pages 1943-1961
I. Scheider and W. Brocks

To remove mesh bias and predict a crack path with cohesive zone model, following reference may be of interest to people using cohesive models and stuck due to mesh bias.

Mesh-independent discrete numerical representations of cohesive-zone models , Engineering Fracture Mechanics, Volume 73, Issue 2, January 2006, Pages 160-177
René de Borst, Joris J.C. Remmers and Alan Needleman

I still remember those days when i was using cohesive model in simulating interface fracture. Breath taking and sometimes frustrating, i would say.:)

Best Regards,

Amir

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Nature does not care whether you can describe a phenomenon by an equation. It just manifests them.
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Thank You very much for all replies.

I just wasn't sure whether Abaqus can handle with remeshing while predicting the crack propagation, but now I will try to look at the problem using "Dynamic element dylatation" suggested in first somment. I will study the documentation advised by Zhenyu Xue and I will try to get more familiar with the problem.

Thank You one more time

Best regards

Michael Borowicz

Dear All:

 I am very interested to hear about the possibility of embedding X-FEM in  ABAQUS. I agreed with  Jinxiong who has mentioned about this possibility. It is a very appealing approach to simulate crack propagation. How to do that? Any ideas? Or maybe someone already did.

Right now, I am using ABAQUS to get the stress intensity factors (KI, KII, and KIII). To get crack growth, I am using a simplified numerical procedure starting with the Paris's law.  I would like to use X-FEM to continue the work from ABAQUS.

I was wondering how X-FEM can be used from here to simulate crack propagation. Also, could you please tell me how I can get a version of XFEM-LSM?

Any advice will be greatly appreciated.  Thanks.

Regards,

David.

Dear all,

I'm also of the opinion that ABAQUS capabilities are very powerful and are worth using. We're modelling 2D crack propagation in fretting fatigue problems (i.e. under contact effects such as those due to square ended or cylindrical indenters). We use X-FEM embedded in ABAQUS via UEL, enabling the introduction of extra dof (this must be something very similar to what Xiujun Fang mentions above). We pre-process and post-process the information using Matlab as an interface. In this way, we benefit from the contact procedures and non-linear solver capabilities of ABAQUS in combination with the great advantages of X-FEM. We presented this work at a computational mechanics conference in Lisbon last year. In a similar way, we have also used the more general approach of partition of unity to enrich the singularity that arises at the end of a squared ended contact zone under a sliding condition  (also combining  X-FEM+ABAQUS). This was presented at WCCM in LA last summer. Some journal papers are now under review. This is joint-work with N. Sukumar at UC Davis.

Since we have realized that the ABAQUS implementation of X-FEM may be of interest to many researchers, we are preparing a paper focusing especially on the implementation aspects and LEFM applications. Once we "clean and tidy up" the code, we'll be glad to make it available as an open-source code.

 Regards,

 Eugenio.

You might be interested and thanks.

1.   Xie D and Biggers, Jr. SB, Progressive crack growth analysis using interface element based on the virtual crack closure technique, Finite Elements in Analysis and Design, 42(2006): 977-984. (Science Direct Top 25 Hottest Articles, #4, Apr-Jun, 2006, #11, Jul-Sep, 2006)

2.   Xie D and Waas AM, Discrete cohesive zone model for mixed-mode fracture using finite element analysis, Engineering Fracture Mechanics, 73(2006): 1783-1796. (Science Direct Top 25 Hottest Articles, #2, Apr-Jun, 2006, #8, Jul-Sep, 2006)

3.  Xie D, Waas AM, Shahwan KW, Schroeder JA and Boeman RG, Computation of strain energy release rate for kinking cracks based on virtual crack closure technique, CMES: Computer Modeling in Engineering & Sciences, 6(2004): 515-524.

Some other papers with application of VCCT and DCZM are

1.      Xie D and Biggers, Jr. SB, Delamination growth and residual strength of compressively loaded sandwich panels with stiffness tailored face sheets, Journal of Sandwich Structures and Materials, in press

2.  Qian Q and Xie D, Analysis of mixed-mode dynamic crack propagation by interface element based on virtual crack closure technique, Engineering Fracture Mechanics, 74(2007): 807-814.

3.      Xie D and Biggers, Jr. SB, Calculation of transient strain energy release rate under impact loading based on virtual crack closure technique, International Journal of Impact Engineering, 34(2007): 1047-1060.

4.      Xie D, Salvi AG, Sun C, Waas AM, Caliskan A, Discrete cohesive zone model to study static fracture in a plate of textile braided carbon fiber composites, Journal of Composite Materials, 40(2006): 2025-2046.

5.      Xie D and Biggers, Jr. SB, Strain energy release rate calculation for a moving delamination front of arbitrary shape based on virtual crack closure technique, Part I: Formulation and Validation, Engineering Fracture Mechanics, 73(2006): 771-785. (Science Direct Top 25 Hottest Articles, #6, Jan-Mar, 2006).

6.      Xie D and Biggers, Jr. SB, Strain energy release rate calculation for a moving delamination front of arbitrary shape based on virtual crack closure technique, Part II: Sensitivity Study on Modeling Details, Engineering Fracture Mechanics, 73(2006): 786-801. (Science Direct Top 25 Hottest Articles, #20, Jan-Mar, 2006)

7.      Xie D, Chung J, Waas AM, Shahwan KW, Schroeder JA, Boeman RG, Kunc V, and Klett LB, Failure analysis of adhesively bonded structures: from coupon level data to structure level predictions and verification, International Journal of Fracture, 134(2005): 231-250.

8.      Xie D, Waas AM, Shahwan KW Schroeder JA, and Boeman RG, Fracture criteria for kinking cracks in triple material bonded joints, Engineering Fracture Mechanics, 72(2005): 2487-2504. (Science Direct Top 25 Hottest Articles, #3, Jul-Sep, 2005, #13, Oct-Dec, 2005)

Hello Dear all.

I am working on my project , encountering with one problem about how i can use element spilliting methode with my desired criteria in abaqus whether  using abaqus toolbars or with introducing subroutine

is any one can help me?

thanck you in advance 

what kind of problem you are going to solve? Do you mean element split or node split?

i am particularly new to fracture mechanics. and new in solving ansys and abaqus software does any body have the idea how the software like ansys and abaqus calculates stress intensity factors and j-integral

Regards

Zoeb Lakdawala

Hi Zoeb,

I have some experience of calculation of stress intensity factors by using ANSYS software. Can you describe what type of problem do you want to solve? And also if you go to verification problems in ANSYS help, in verification problem 143, there is an example input file for you to calculate stress intensity factors in a plate having a crack at the center of the plate.

Regards,

 Erkan.

a shell having an internal pressure of 10.54 bar having a crack of elliptical shape.

Iwant to simulate residual stress in inner portion of a pipe in ABAQUS Please HELP ME!!!

Hi all,

I am now learning strain localization in solids and geometerial by using Embedded Strong Discontinuity theory (EFEM or elemental enrichment).  I am looking for an open source code to learn how to understand and how to reproduce some examples by using EFEM. Did anyone know that?

Any advice will be appreciated.

Cheers.

hi

any one have idea about how to use zencrack for cracking ,, how i get this software ( free download link) , please let me know

i have to simulate the crack progation in annular disk for my project work

tnks

thanks for the link , but i was wondering, that we can use only up 40 element or some thing , with this limitation i am not able complete my project , as my model will be having some 1 Lakhs element.

so could u tell me how can i can solve my problem.

thanks & regards

Dear All

I'm working on studing the use of metal foam in sandwich structre containing Al or steel plate to overcome an impact shells or plates at differnet impact velocity but the prblem that I face how to define the failure critrion of Meat foam except difine the crushable foam properties, and I've read a paper on using cohesive element but i don'nt know how to use it.

Hopefully some one can help me solving this prblem, by the way I'm using ABAQUS v6.6

Regards

Hi everyone,

I have a lot of doubts:

1) i wonder if it is posible to find the plastic zones trough abaqus arround the crack tipi.

2) What do i need exactly to define a crack in a viscoelastic step?

3) When i ask the hystory output for the J-integral how can i interpretate the graphics and how can i know if its working because in the model, in visualization nothing is happening is almost the same figure that in the asembly.

Iknow is alot but is really important, so thank you in advance for helping me.

Violeta

hi guys,

i am going to simulate material failure by using Johnson-cook pasticity and damage model, but i need to split my elements when the material fail, so i have some questions:

1- how can i split element ( or nodes) in my model to show the effect of material separation

2- is it going to work with ALE formulation implemented in Abaqus? 

i did some simulations but when it starts for plasticity calculation it exit with ERROR CODE 5 or 114? do you know whats that?

Regards

Hassan

Sheffield 

hello

I read the above intersting discussion. I have a doubt, whether I can give my own fracture criterion in ABAQUS. I am trying to simulate crack propagation using ANSYS right now I am using Max normal stress criterion now I want change fracture criteron. I want to include fracture toughness along with max normal stress can I able to implement in ANSYS or is there any provision in ABAQUA

Regards

Gouse 

Dear All,

can anybody help me to Model an Elliptical surface crack.Please give me an instruction manual kind of thing . Otherwise  mention where to start whether in ABAQUS/CAE or in ABAQUS/Explicit.

Thanks in advance. please respond......... 

Regards,

MVN 

Hi All,

I'm presently working on modelling of guided ultrasonic wave scattering at defect using Abaqus/CAE. Can anyone help me with some tutorial materials on modelling of crack or notch in a through-hole of a plate as well as loading the model with Lamb Wave?

Warm Rgrds.

Jo Ukpai

JIU

Hai Zhenyu Xue,

Hope you are having rich experience with ABAQUS. Can you please help me in " Modelling a Surface Elliptical Crack ( Quarter Plate)". If you have any kind of notes on the same please forward it. Otherwise atleast tell some source  from where I can get the help in this regard.

Thanking you

MVN