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Fracture in Abaqus

Michael Borowicz's picture

Good morning

 

I'm working in Abaqus on modelling crack propagation. Regards this i have two questions.

1)I would like to ask if it is possible for Abaqus to create automatic propagation in 2D. What should I do to receive the effect. I've defined the crack and in the history Output i've defined the crack initiation criterion. There are no warnings, no errors, and in visualization module the effects are miserable.

2)When I'm trying to plot Crack prop. direction I'm receiving only points in vertical for time=1s, and I would like to receive crack propagation for different state of times, different moments.

P.s. Sorry for my english, I hope everything is clear enough to understand this post. I hope someone can help me.

Regards

Michael Borowicz

Zhenyu Xue's picture

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

Hi Zhenyu Xue

I want to simulation of fatigue crack propagation in abaqus, But lost my abaqus manual.if you can help me by explaining which steps I have to do for simulate, I am really thankthful.

I usually late check this web page.

mohamadreza86@gmail.com , Is my e-mail and I check it every day!

surendran47's picture

Hi I am using ABAQUS 6.9 and have 6.10 also

Can you explain how to do a crack propagation. in any of the above mentioned versions

Hello sir,

Can you tell me how to visualize the two  differnt temperature with respect time on a single axis?

Hello Surendra,

Same type of problem am also facing in Abaqus/CAE.If you will do and someone send tutorails .please send me reply also.

Thank you.

It is maybe a bit late, but I learned using XFEM in Abaqus by Matthew Pais in "http://www.matthewpais.com/abaqus".

There are a lot of examples with tutorials (step-by-step in CAE), the cea-files and the inputs, that you can use for learning it. He works with 6.10.

I think, you already have learned it within the 2 years :-)

Hello Everyone,

 

I am new in this forum.I am trying to model Fibre reinfored Polymer fracture in ABAQUS . But, In website I could not find any example for that.I have done fracture model for isotropic material such as Alluminium using Contour Integral.But, for this FRP I am being unable to model   it.What should be my consideration (different from isotropic) using this contour integral.I want a tensile matrix cracking or matrix-fibre interface cracking or fibre cracking. Please help me in this regard.

 

Thanks & Regards,

Dipak Rakshit

dipak.r2@gmail.com

Yanfei Gao's picture

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

Henry Tan's picture

Dear Yanfei,

I am reading your paper

Y.F. Gao, A.F. Bower, "A simple technique for avoiding convergence problems in finite element simulations of crack nucleation and growth on cohesive interfaces." Modelling and Simulation in Materials Science and Engineering 12, 453-463, 2004

with great interest and want to raise some questions for discussion.

In your paper, you applied your technique (by introducing a small viscosity in the interface cohesive law) to a system having only one crack. Can this technique be applied to a system with many cracks, or say just two cracks, in the case when all those cracks are reaching their strength peak?

Hi Yanfei Gao
I am working on crack propagation problem using cohesive elements but I really do not know how to choose the properties of cohesive element. Can you tell me how to choose it??

Hi,

I'm new in this forum. Iwould ask Mr Gao in order to explain some things. So, I'm working on cemented fixation of orthopaedic implant. My model was consists of three parts: implant, acrylic cement and bone. Thus i'm having two interfaces, the one between implant-cement and another betwenn cement-bone. I would to simulate the pull out test of the implant. What the nature of  intéraction in the different two interfaces. How  simulate my problem without any subroutine. WHAT do I do if I WOULD predict the damage and the failure of the interphase.

thanks for answer me

and I'm very sorry for my Bad english

V. Bheemreddy, K. Chandrashekhara, L. Dharani, and G. Hilmas,
"Modeling of fiber pull-out in continuous fiber reinforced ceramic
composites using finite element method and artificial neural networks,"
Computational Materials Science, Vol. 79, pp.663-676, 2013.

http://www.sciencedirect.com/science/article/pii/S0927025613004278

Zhenyu Xue's picture

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:

 

If a singularity-based approach can handle it, the CZ model can do it too. In place of K-based criteria, damage induction criteria (similar to yield criteria of plasticity) can be devised based on stresses at the fictitious crack tip to simulate arbitrary crack growth within the CZ model.

The "blast" case you mentioned I would not consider right now a conventiional frature problem we would typically think of dealing with individual cracks, because there are just too many cracks in a blast. The cohesive element model plus some complicated consitutive law applied to the volume seems to me the best approach for the time being. Maybe one day the computer technology has advanced so much, we could simulate all those indivual cracks as indivisuals.

 

Bo

Yanfei Gao's picture

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 

Henry Tan's picture

Dear Yanfei,

You modified the traditional cohesive elements by introducing a small viscosity in the interface cohesive law.

Will this affect the compliance of the system?

Dear Prof. Gao,

I deals with cck propagationsimulations initiated from indenter. Ialready created the model for indentation in ABAUS Explit, it worls well, bt i haveno idea how to plement the cohesive elements in it. The best way i think to introduce tese elements via ABAUS CAE. Could you please give me some hints whee can i find the tutoials fr cohesive elements.

Best regards

ABAgirl

Amir Siddiq's picture

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 MechanicsVolume 70, Issue 14September 2003Pages 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 MechanicsVolume 73, Issue 2January 2006Pages 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

*******************************************************
Nature does not care whether you can describe a phenomenon by an equation. It just manifests them.
*******************************************************

 

Henry Tan's picture

In the eXtended Finite Element Method (XFEM), the interface discontinuity can be well solved.

Xiujun Fang's picture

Dear Henry,

Maybe the method you metioned above  is a good choice for problems about moving discontinuities. I am using X-FEM to simulate fracture process in ABAQUS. The user subroutine of UEL is used to construct special element with enriched DOFs. The X-FEM can make use of the powerful ability of solving nonlinear equations of ABAQUS or other FE commercial software.

Xuanhe Zhao's picture

Hi Xiujun,

Some of us have realized how powerful ABAQUS can can be, e.g. http://imechanica.org/node/470. It's such a good idea to take advantage of ABAQUS to perform X-FEM calculation via UEL. Is there any open-source X-FEM subroutine for ABAQUS? I noticed Prof. Y. Gao has posted some UEL subroutines on line (refer to publication 7). Is there more?

-XH 

Xiujun Fang's picture

Dear XH,

I have ever tried to search the open-source X-FEM subroutines for ABAQUS but  can't find any more than you mentioned so far( Eugenio's work is expected). According to my experiences of writing UEL I find it is difficult to develop a robust program individually. A lot of work which have little relation to X-FEM itself takes much time. If there are a few ones to do the similar thing, maybe joint-work is a choice to avoid the repeated labor. I will be very glad to share my program with others.

Jinxiong Zhou's picture

Dear Xiujun,

You propose a very appealing approach to simulate crack propagation by embedding XFEM into ABAQUS commercial code. As far as I know, XFEM can also be implemented by a combination of XFEM and Level-Set method, eg. the work by Ji and Dolbow (IJNME, 2002). This new version of XFEM-LSM can be used to simulate a variety of time-dependent moving boundary problems. The key of the strategy is to solve a time-dependent mechanical equation as well as a level-set update equation. My question concerns whether it is possible to implement solution of  these time-dependent equations in ABAQUS. If that is a case, then simulation of dynamic crack propagation is possible! Can I have your comments?

Xiujun Fang's picture

Dear Jinxiong 

The question you mentioned is interesting and forsighting. I am not sure I understand you correctly .The dynamic crack propagation problem may be understood in two ways: 1) considering the velocity of crack propagation itself;2) only taking account of the inertial force without considering the v of crack propagation. The latter is relatively simple and there is no foundamental differences but the dynamic loadings between the static problem and dynamic problem. XFEM-LSM embedded into ABAQUS can be used to simulate the problem in this case. I am trying to simulate the dynamic response of gravity dam with crack propagation under earthquake. As for the former I am not sure. But I think it is hopeful to realize it.

Jinxiong Zhou's picture

Dear Xiujun,

My question is actually the first case you mentioned, i.e., unsteady crack motion with fast speed. In this case, crack velocity is an important factor and may be comparable with shear wave speed. One of Karma's phase field method simulation results show that the crack velocity,v, can reach 0.4c, where c is the shear wave speed. The conventional steady-state crack propagation criterion will be inaccurate in this case and crack branching and instability may observed. This problem is really challenging!

Jinxiong

Hi everyone,

I am currently working on modelling XFEM. I noticed that you are alot of experience in using XFEM. I am running two different models in one .cae file. The first model, is a creep model, which has 10 steps. The seond model is XFEM model.

I am trying to run the creep model, import the strain values from end of each step and import these values for every step into XFEM, to find out when fracture takes place. I have changed the frequency number to 1 for each othe steps, to make restart request. 

I have then used the predefined field in first step of XFEM, to import the strain values for the first step of the creep model. When I try to do the same thing for the second step in XFEM model, it doesnt allow me to select the model anymore, saying that the part is already in use for an existing predefined field.

I was therefore, wondering if you know how to import strain values for each step into XFEM without coming across this error?

Thank you very much,

Sam 

Hi Amir,

         I am
doing the similar project like what you did. My project is to predict
the delamination pattern in the interface of a bi-layer system
(substrate and overlay) using ABAQUS. Substrate is made of normal
concrete and overlay is made of High-Performance concrete. Delamination
is induced by maintaining high temperature (say 95 F) in the enclosed
room due to which different materials used will absorb different
temperatures and because of this difference of temperature in two
layers, shear stresses are developed at the interface due to which the
delamination occurs.

My questions are: What are the properties required to input in ABAQUS?

How to model the interface?

How to input the temperature loads?

Any suggestions will be appreciated. Thank you very much Sir. 

    

Sathish konduru.

West Virginia university

Amir Siddiq's picture

Hi Sathish,

You might know already about them but as starting point, basic ingredients of the cracking behaviour would be:

- construction of an optimized finite element model with proper assumptions of loading, boundary, symmetry, etc conditions and size, type of elements,...

- selection of approperiate material model for the material, and identify or obtain the corresponding material parameters (most likely from experiments or literature search).

- There are different material models already available in ABAQUS based on concrete cracking, damage plasticity, etc. Please, have a look in the documentation and see if you find anyone of them useful. Although, I am not sure if they are based on thermal loading or not. Otherwise there is always a possibility to write a user material subroutine.

- In most of the cases you must know the crack path apriori to perform crack propagation analyses in ABAQUS. Do you already know?

- Another tedious way would be to find the potential direction of crack propagation and separate nodes in that direction but it is a tedious job to do. You might need many steps/increments etc.

 - There are many criterion present, based on your explaination a criterion based on shear stresses might serve the purpose but not sure until further details of the experimental results are known.

 I hope this helps. Please let me know if you require further clarifications.

All the best. ENJOY THE BUMPY RIDE.:) and never lose hope.

Amir

Michael Borowicz's picture

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.

Jinxiong Zhou's picture

Hi David,

Your research is very interesting. The key idea of XFEM is an enrichment of additional DOFs which may include some information of problems, e.g., the singularity of crack tip, the topology description of the level set function. Enrichment of XFEM for static problems is possible and actually some researchers have succeeded. My previous comment was wondering the difficulties involved in dynamic problems. Maybe this also has been realized by someone in ABAQUS. Can anyone tell me some related works?

There is an open XFEM++ website by Prof. Stephane Bordas.  Hopefully it can help you!

Jinxiong

David,

your reply awakening to do more for my research on crack simuation. Could you please indicate how to determine stress intensity factoers (Ki,KII and KII) using ABAQUS? I highly appreciate for your time.

 

-arasu

 

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.

Dear all,

Just in case it is of interest to some of you, we provide links to three postprints related to our Abaqus implementation of the X-FEM. The latest is an "article in press" in Eng Frac Mech where we explain the essentials of the implementation and provide a link to the source code for the Abaqus computation. Note that the implementation is limited to 2D and the pre-processing code needed for element subdivision is not provided.

The other papers are an application to crack growth under fretting fatigue conditions (published in IJSS) and a specific enrichment of the singularity of a sliding corner (published in IJNME). We hope that these three publications may be helpful.

Best regards,

Eugenio.

The references and the link to the blog entry where the postprints are available: 

Giner E, Sukumar N, Denia FD, Fuenmayor FJ. Extended finite element
method for fretting fatigue crack propagation (2008) IJSS, 45,
5675-5687.

Giner E, Sukumar N, Fuenmayor FJ, Vercher A. Singularity enrichment
for complete sliding contact using the partition of unity finite
element method (2008) IJNME, 76, 1402-1418.

Giner E, Sukumar N, Tarancón JE, Fuenmayor FJ. An Abaqus
implementation of the extended finite element method, EFM, DOI:
10.1016/j.engfracmech.2008.10.015.

http://www.imechanica.org/node/4338

De Xie's picture

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 

De Xie's picture

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

Zoeb Kaizar Lakdawala's picture

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

Erkan Oterkus's picture

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.

Zoeb Kaizar Lakdawala's picture

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

Hello Prashant:

For details, you can use this link: 

http://www.zentech.co.uk/zencrack_download_evaluation.htm 

Cheers.

 

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,

To your question 1):

You can define the field output PEEQ (Equivalent plastic strian at integration points) , then you can check the plastic zone afterwards.

 

Xiaobo 

 

H.Ghadbeigi's picture

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 

Gouse's picture

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 

Dear all:

  I'm here just to mark the topic. I major in concrete fracture modeling and simulation using numerical methods such as FEM, NSPIM, EFGM. I have a lot of questions about the simulation of crack surface, concrete crack model, and SIF's calculation. I wish to communicate with any one in a similar subject.

       my email: mscj042@hotmail.com

qq:42246504

Dear all,

 To find principal values of stress and strain tensor, I'm gonna use the inbuilt subroutine SPRINC in my Abaqus UMAT.

Can anyone tell me how I can use this subroutine in a user material Fortran code. In the Abaqus documentation, I found some description of how to call the subroutine but after doing the same procedure I received error code 144!

Gyanender Singh's picture

Hi Everyone,

I am doing a project in which I am trying to study about the
drilling of composite. The aim is to optimize the drill and process
parameters to minimize the damage. For this I have tried to simulate
the drilling process in ABAQUS and I am using the Hashin damage model.
The problem is that Hashin damage model works only for the lamina which
takes only plane stress elements. Since only plane elements are allowed
I am unable to simulate cutting action of drill as the composite plate
is effectively 2D.

 When I take 3D elements then Abaqus shows error that Hashin damage
model cannot be applied for that plate. Also there is no other damage
model for composites in Abaqus.

 As a result, I am stuck in this project. Please suggest.

Thanks

Gyanender

Dear all, 

I am a master student doing project related to non-linear fracture. Colud you please tell me how to model and perform the non-linear analysis of a plate with edge crack using ANSYS

please anyone help me

Regards

Aswin 

hi Aswin,

please refere to ansys verification manual VM256 and VM 143.

Hello All,I have simple question.. I am involved in studding Nonlinear Fracture mechanic for case (thick plate) type of structures.  Question - What material parameter ABAQUS xFEM will require?  or Is there any example you can point out in ABAQUS xFEM... any help would be good starting point for me.My goal is to Compare Nonlinear Fracture mechanic analytical model with test specimen.  Then develop some short of basic guideline for acceptance criteria for crack part.Regards,

Hp

 

 Dear All:

I am working on crack propagation problem using cohesive elements but I really do not know how to choose the properties of cohesive element. Can any body tell me how to choose it??

 

Vikas

 

hello all,

am working in ABAQUS on crack propagation problem. have a query

actually  i basically need automatic crack propagation i.e., i vl be defining the crack on the boundary and all the necessary details, also defining the crack in the history output

how shall i get crack propagation?? 

i need it without using any model or without using any subroutine...

can anybody plz answer my query...

regards,

nithesh 

for the research.

Before all the numerical algorithms, do we understand the nature of dynamic fracture, or say, have we discovered any reliable criterion for dynamic crack propagation?

The quasistatic crack propagation has become friendly though, at least, in homogeneous materials.

It seems a lot of us have stopped writing a code of our own. Is this so in order to graduate sooner?...

 

Bo

Please could you tell me how I can get the SIF at the crack tip in abaqus cae! I am modeling a static 2D case where the crack is horizontal, I want to see the accuracy of SIF as the mesh becomes finer?

Thanks!
Peter @coupon codes

Reza Hojjati's picture

Hi everybody

I have created ABAQUS *inp file and I am going to open this file in ANSYS in order to use the model for crack initiation analyze.

Is it possible or not. if no is any prepared code available to translate it for ANSYS?

Hi every one,

i am new in this field.

would you please introduce me any step by step modeling of  3D edge crack modeling with J-integral method ?

i can model it in 2D, but have problems in 3D

regards,

hi every body

i simulated a rigid projectile and deformble target, i used Weldox 460 E Steel for target and use "Johnson-cook" model for damage, but i cannot define 'Damage evolution" ! i mean whwn i going to use "Displacement" for damage evolution i cannot find a good value for "Charactersic Length" !  element size for target is 0.2*0.2*0.2mm^3,

can any body help me?

best regards

Hello every one, 

Please some one tell me how I can get the SIF at the crack tip in abaqus cae! I am modeling a static 2D case where the crack is horizontal, I want to see the accuracy of SIF  as the mesh becomes finer.

 

Thanks,

Reza 

laxmi512's picture

Hi...

I am working on two cracks emanating from each circular hole.

In ansys we can only model one crack at a time.

So can anyone pls suggest how to model a plate containing multiple cracks.

 

Thanks,

Laxmi 

rdalmeya's picture

Dear sir
        I am Ravi dalmeya doing Phd from Indian Institute of
Technology,Kanpur (India). I am doing work on adhesive elastic wavy 
thin film. I have completed 2-D Hertzian contact between cylinder and
elastic half space using Abaqus. Now i want to apply Dugdale-Barenblatt
cohesive zone model outside the contact zone and i do not know  how to
apply  Dugdale-Barenblatt cohesive zone model outside the contact
zone.Can you give me some suggestion?

Thanking you

Ravi dalmeya
Phd scholar
IIT Kanpur (India)
email  rdalmeya@iitk.ac.in

Hello every one, 

Please some one tell me how I can get the extract force on the weld joints in abaqus cae(static Analysis)!

How to Extract force on surface ...What option in Abaqus cae

 

Thanks,

Prasanna

marco.paggi's picture

Dear All,

in this recent article you may find how to select the properties of the cohesive zone model (stiffness, and so on) according to physical arguments:

 

M. Paggi, P. Wriggers: "Stiffness
and strength of
hierarchical polycrystalline
materials with imperfect interfaces", Journal of the Mechanics and
Physics of Solids
, in press,
doi:10.1016/j.jmps.2012.01.009

 

This has been possible by proposing a new CZM for finite thickness interfaces:

 

M. Paggi, P. Wriggers: "A nonlocal
cohesive zone model for finite thickness interfaces – Part I:
mathematical formulation and validation with molecular dynamics", Computational Materials Science, Vol. 50 (5), 1625-1633, 2011.doi:10.1016/j.commatsci.2010.12.024

 

Here you may find its implementation in the finite element code FEAP:

 

M. Paggi, P. Wriggers: "A nonlocal
cohesive zone model for finite thickness interfaces – Part II: FE
implementation and application to polycrystalline materials",
Computational
Materials Science
, Vol. 50 (5), 1634-1643, 2011. doi:10.1016/j.commatsci.2010.12.021

 

Best regards,

Marco Paggi

Hello,

i have a problem in the value of J (Rice's integral); i obtain an error message ' The j-integral values are negative. Please check if the specified q-vector or crack surface normal is correct '

how should i choose the direction of the crack?

Regards

 

plz some body answers me!

what is the difference between using the XFEM directly from abaqus standard and using a UEL subroutine?

thanks

Hi,

i'm trying to simulate crack propagation(2D) with the use of a crack length versus time criterion.However, there are two error messages that i dont undrestand: 

i Only *surface behavior, pressure-overclosure=hard may be used if *initial condition,type=contact is specified

 

*surface behavior,augmented lagrange keyword cannot be used if *initial condition,type=contact is specified

 

can anyone help me?

thank you 

balaji227's picture

hello

         i'm trying to modell the debonding behaviour of FRP from FRP strengthend RCC Beam. i'm facing problem in ABAQUS

1. Modelling RCC Beam

2. Using Concrete damage plasticity Model 

3. Modelling Cohesive zone

                     any suggestions with respect to any of the above will be very helpful.

 

thank you

bala

Dear Friends,

 I want to model crack initiation and propagation in top surface of a bilayer with XFEM in ABAQUS. I modeled the contact process of two layers only and got the results successfully. but i face error when i add xfem analysis in my model. could you please guide me how to solve the problem?

 with the best,

ehsan

Hello Everyone,

 

I am new in this forum.I am trying to model Fibre reinfored Polymer
fracture in ABAQUS . But, In website I could not find any example for
that.I have done fracture model for isotropic material such as
Alluminium using Contour Integral.But, for this FRP I am being unable to
model   it.What should be my consideration (different from isotropic)
using this contour integral.I want a tensile matrix cracking or
matrix-fibre interface cracking or fibre cracking. Please help me in
this regard.

 

Thanks & Regards,

Dipak Rakshit

dipak.r2@gmail.com

Dear all

i want to investigate effect of crack in lamb wave
propagation in composite plate in abaqus software. to this end, i have
modeled a composite plate using 3Dshell defomable planar part. Also, i
modeled crack using seam tool. i have problem in defining contact
between two edges of crack to transmit wave through it. can anybody help
me please?

Hi everyone

I am new user in Abaqus, i read most of the posts related to the modelling the crack but unfortunately i didnt get a clear procedure, maybe it is due to my weakness in this software.

i want to model a crack in abaqus and analysis the crack propagation, actually i am working on piezoelectric material, but i want to know,  can you tell me different steps to model a crack and then how to analyze the propagation on it.

Please help me is this case.  

Dear friends:

I had a problem,In the ABAQUS how to deal with bimaterial problem, I want to model the crack of bimaterial problem by XFEM in ABAQUS,but I don't know how to model the Material interface ,such as meshing,enriching node,ect...

 can anybody help  me please? Best wishs for  you!

Hi all,

I'm doing my project in glass beam of 4 point loading in abaqus 6.12and I'm new to model in abaqus. i don't knew what are the properties to be inputed into abaqus for glass brittle material and how to find the first crack in the beam. 

Hi all,

I am new to Abaqus. I've just started using it. I am just trying to model a plate under plane stress with a edge crack. I had a couple of doubts.

 

1. XFEM doesn't give me the values of SIFs. Is this alright or is there a way to extract it?

2. I wanted to obtain STrain energy release rate values. I'm unable to add a history output request, so I asked for the STrain energy release rate values under the file output option. But I'm unable to get any values on my DAT file.

3. I get a warning message that says "STRAIN OUTPUT REQUEST LE IS NOT VALID FOR SOME ELEMENTS IN THIS ANALYSIS. THIS REQUEST IS SWITCHED TO THE STRAIN MEASURE, E." I didn't change any default settings. How do I get rid of this? Is this the reason I'm unable to get the SERR values?

 

Please help.

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