iMechanica - Fracture Criterion - Comments

simulate crack

K Kamarudin — Mon, 01 Aug 2011 21:50:22 -0400

hi,

i am a new learner of using abaqus.i would like to know whether there is a possibility of simulating a brittle material until cracks appear? i have read that we need to introduce an initial crack?are we not possible to simulate a solid brittle material without having initial crack?

i hope someone out there can advice me on this matter. your help is much appreciated.

Hello all, I am trying to

HussamNasreddin — Mon, 06 Jun 2011 04:47:31 -0400

Hello all,

I am trying to model concrete as an elastic material in ABAQUS. The
model can be any simple structure (cube, beam or column) but the main
feature is that concrete behaviour is elastic up to a limiting strain
(St. Venant's theory). Which of the Failure criteria in ABAQUS i should
be using (Elasticity or brittle cracking)? if neither would you mind
explaining other options?

Thanks

Hussam

Auxiliary Fields for Interaction Integral

Matin Parchei — Mon, 30 May 2011 09:32:22 -0400

Dear friends,

I am writing an XFEM code fordynamic crack propagation and interested in using the Interaction Integral method(as in Rethore et al. (2005)) for computation of Stress Intensity Factors(SIFs). I wonder if anyone knows what kind of dynamic asymptotic crack tip auxiliaryfields could be applied to the method for computation of SIFs for a dynamicallypropagating crack.

Regards

Matin

additional information on the topic

Salamander777 — Fri, 06 Aug 2010 04:44:47 -0400

In order to optimize the blanking processes, it is important to
identify the conditions within the deforming workpiece which may lead
to fracture initiation and propagation. Within this framework,
numerical simulations are widely used in industries to optimize sheet
metal forming processes. However, in order to have a confidence in the
results of such simulations, an accurate material model is required.
The accuracy of a material model is affected by the constitutive
equations and the values of the material parameters. In order to reduce
the danger of fracture of metal parts during manufacturing processes,
advanced optimal design requires knowledge of critical values of some
fracture criteria of the material used.
There are some good reads in pdf on this topic on the web. Might be useful for
the readers.
http://www.pdfok.com/fracture-criterion

CTOD and J-Integral

SIVAKUMAR M V N — Thu, 21 Jan 2010 13:27:52 -0500

Dear Vikas,

You can get J-Integral directly from 'History output requests'. Select History output requests and Contour integral domain. and for the second one CTOD can be evaluated from finite element displacement and 45 degree intercept concept.

can you tell me how to evaluate LLD..?pls..

MVN

How to evaluate Crack growth in ABAQUS/EXPLICIT

SIVAKUMAR M V N — Thu, 21 Jan 2010 13:22:50 -0500

Dear All,

I am using ABAQUS/EXPLICIT for analysing a cracked body.Is there any way to calculate crack growth in EXPLICIT.? somewhere I have seen that " priciple stress/strain element failure approach" can be used. if it is so how to implement it..?

Can anybody help me in this regard.

MVN

Cohesive elemet propeties

vcvikas — Tue, 01 Sep 2009 14:25:43 -0400

Hi Panierstef

I am modeling a crack propagation problem using cohesive elements. But I really don't know, how to choose the properties of cohesive elements? Can you help me in this regards.

Thanks

Vikas

Hi De Xie I am

vcvikas — Fri, 28 Aug 2009 12:34:39 -0400

Hi De Xie

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??

Vikas

regarding results in ABAQUS

vcvikas — Mon, 03 Aug 2009 02:54:22 -0400

I have prepared FE model for crack growth analysis in ABAQUS. I want to know that how can we get out put results? e.g. CTOD or J- intergral values. I am getting LLD. Plz help me.

GYFM

vcvikas — Sat, 04 Apr 2009 00:42:14 -0400

Sir

GYFM means Gerenal yielding fracture mechanics. in this cateragy there is large plastic zone ahead of crack tip and it is applicable for thin sheets.

GYFM ?????

PANIERSTEF — Mon, 23 Mar 2009 16:07:40 -0400

Sorry what's means GYFM

VCCT in GYFM

vcvikas — Thu, 19 Mar 2009 00:23:41 -0400

Dear Sir

Can we use VCCT in GYFM?

Fracture criteria for LEFM

AS — Sat, 14 Mar 2009 18:03:57 -0400

Hi,

I find this topic pretty interesting. A broad
literature has been devoted to it and to a similar one (see
http://imechanica.org/node/1692). Myself as well gave a small
contribution recently published in Journal of the Mechanics and
Physics of Solids, 56 (2008)
2092–2116. A few mistakes and some further developments have been
considered in another note, submitted presently to Engineering Fracture
Mechanics. My conclusion is that most criteria for crack propagation in
the small scale yielding range, and SED among them, have several
weaknesses and should be carefully considered. But of course I
can be wrong.

Any comment on this is sincerely appreciated.

Hope it helps!
Alberto

VCCT technique

PANIERSTEF — Thu, 12 Mar 2009 12:27:03 -0400

Dear vcvikas,

The node release method available in Abaqus is Virtual Crack Closure Technology (VCCT). You can use too the cohesive elements. One of the differences between theses 2 methods is that VVCT method assume that you have an initial crack.

Theses methods assume that you know the crack path (for example delamination). If you want to study the bifurcation of the crack, you must use remeshing tecnique and crack font advance. XFEM method are very efficient to study this kind of problem.

Regards

Stephane

How to develope a model for crack propagation

vcvikas — Thu, 12 Mar 2009 10:34:46 -0400

Hello friends

I am doing my research in fracture mechanics. Presently I am working on crack propagation FE model using ABAQUS software. I am new user for the software. Can any body tell me that where I can find the interactive tutorials for crack propagation problems or any idea, how to proceed for the same using ABAQUS software? I heard that there is a node release technique in ABAQUS software to solve such problems, but not able to use it.

Fracture Criterion

Arash Karpour — Fri, 13 Jul 2007 02:27:08 -0400

This is either a wage question I am asking or a stupid one...

How many fracture criterion do we have and what are they? some of these criterion that I am reading are related or a form of others...For example CTOD (crack tip opening displacement) criterion is related to energy release rate in

" A CTOD-Based Mixed-Mode Fracture Criterion" by Fashang Ma et al.

Any guid or direct help would be much appreciated.

Thanks for your time

Arash