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Fracture Mechanics Forum

smilehan001's picture

problem when using chesive element, seeking help

Hi, I use the chesive element to simulate the debonding of particle in matrix.
I edit the mesh to make the thickness of chesive element to be zero. When I submit the job,
error comes:
The geometry of 30 elements is too distorted. Check the nodal coordinates or node
numbering on elements identified in element set ErrElemDistorted.

If I don't make the thickness to be zero, it goes well with ABAQUS 6.10.
Can anyone help me?

How do I determine if J-integral is needed?

Basically I would like to know if I need to use J-integral to analyze a crack. From what I think I know, the stress intensity factor, K, can be used to analyze crack growth if the plastic zone ahead of the crack tip is within an elastic singularity zone. If the plastic zone is large (i.e. plastic zone is not embedded within elastic singularity zone) then J-integral should be used, correct? This singularity zone is where stress is proportional to 1/r^0.5.

Rerun input file with ABAQUS software from a certain time

Dear,

 

There was a time i run my input file of 3D model with ABAQUS. It was supposed to take more than one day in order to complete analysis. But unfortunately my computer was turned off, then i had to rerun input file from beginning even running process was completed almost 85%. Is there anyone knows the way to rerun input file from the time it was ruptured? 

 

Tuan Son

Fatigue life calculation of a component in multi-axial stress state

I am dealing with a high cycle fatigue life calculation of a component which is under a constant amplitude proportional loading, however this component is in multi-axial stress state. In fatigue life calculation we deal with uniaxial stress. Now which uniaxial stress measure (equivalent, maximum principal, minimum principal or absolute maximum of maximum and minimum principal stress) should be used in fatigue life calculations?

fatigue crack growth curve

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I implement a program for fatigue crack growth in the XFEM.

But I have great difficulties to find material parameters used for PARIS- or  FORMAN/METTU-equation.

Can anyone point me where this parameters could be released, for example for epoxy, polyurethane, 18CrNiMo7-6 and Aluminium.

I would very appriciate your response.

-Sungyong-

Damage Modelling in XFEM

I am currently attempting to model a crack simulation using realistic values for materials such as aluminium and cast iron. I was wondering if anyone knew of a resource which might provide standard values for MAXPE/MAXPS in the damage initation command and for the parameters in the damage evolution command.

Any help would be much appreciated.

 

 

Jez

[SOLVED] 3D crack growth modelling in Abaqus by XFEM

Good day everyone,

I'm new to iMechanica and look forward to getting to know everyone here. Smile

I'm currently doing analysis of interlaminar crack growth in fibre-reinforced composite by Extended Finite Element Method (XFEM) using Abaqus. I'm a new Abaqus user and therefore I have to familiarise myself by constructing random 2D and 3D models with isotropic materials before jumping onto anisotropic.

Experimental data with different specimen sizes for single notch bending test

Experimental data with different specimen sizes for single notch bending test

Hello, everyone 

Hcham's picture

crack progagation whith XEFM

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hi all im using abaqus 6.9 to simulate a crack propagation in an elastic material whith Xfem option, i still have this errors :the following XEFM crack are failling to correctly generate the conditions are listed whith the crack names : crack-1 Failed to locate crack tip.
 and if i submit the job even the warning its abort and i get this error:the damage model has to be specified for enriched element ( nbre) instance part 1-1.i specify the damage  model in Intprop as follow
** MATERIALS
**
*Material, name=Material-1
*Elastic
 2.1e+11, 0.3

numerical modelling of orthogonal machining

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hello guys,

             i am trying to model  machining process especially i am trying to simulate varation of chipreduction coefficient wth uncut chip thickness so can any one send papers regarding this 

so plz help me

Ductile fracture prediction in Taylor Test

I am reading the Weirzbicki's paper titled "Numerical Prediction of fracture in the Taylor test". I do not understand the terms stress triaxility and Lode angle parameter clearly. What does the term "negative stress triaxiality at -1/3" stand for? Kindly explain me these two aspects clearly and also provide some references for reading.

Thanks and Regards,

Siva Prasad A V S.

rajnish0007's picture

How to simulate pull out test in ABAQUS ??

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hello all

How to simulate pull out test in ABAQUS 6.9  ???

mmaaa's picture

fracture mechanics plus matlab

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Hi there

pleas help me with an example explaining how to use matlab code in determining crack growth rate

thank you

mgh's picture

abaqus damages material constants

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hello dears

i have a problem with abaqus in defining material constant for damage initation and evolution(c1,c2,c3,c4)

i dont know the equation that they depend. can somebody help me?

thanks a lot...

Relation between particle size and debonding stress

Hi everybody,

do you know where I can find some informations about the relation

between particle size and critical normal stress at the interface particle /matrix

for a particle embedded in a matrix?

I read the Chen's article 'Size effect of particles on the damage dissipation in nanocomposites'

but this article deals with spherical particles. I am studying clay/matrix nanocomposites and I would like to

calculate the relation between clay size and debonding stress.

Thanks,

Cecilia

FRANC2D/FRANC3D

Hello,

 

I wondered if there are any users of FRANC2D/FRANC3D.  If yes, I would appreciate if anyone have examples of solving transient crack propagation problem for a reinforced concrete structure (preferably with interacting cracks).

Your help is much appreciated. 

 

Thank you,

ss

 

kisku's picture

abaqus

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dear all,

i wanted some codes used in ABAQUS to solve the dynamic problems:

1.Blunt and Hemispherical projectiles hitting the plates.

2.When the plate is perforated by the high velocity projectiles.

hope someone will help me.

regards,

-Sanjay

Punching opereration in ABAQUS

I am trying to simulate a punching process in abaqus but cannot get the model to work correctly.  When the punch hits the blank, it tries to deform the area and then aborts the analysis.  How can I get the mesh to break becuase of the shear stress rather than just deforming?

About estimating limit load using elastic-perfectly plastic material

Hello everyone. I have gotten this question for a long time.

As we all know, people are using elastic–perfectly plastic material to estimate the limit load for a specimen (structure). If the plastic zone is throughout the ligament as the load is increased, we say that the load is now reaching the limit load.

Reading contour integrals from Abaqus output database

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I am trying to read J integrals and K Factors from an Abaqus history output database, but I'm however getting a KeyError for 'setname=_PickedSet24' which is the nodeset generated from abaqus cae for the cracktip node. The problem is symetric CCT model using abaqus V6.8.2.  In addition, as the script aborts at this point, I'm not quite sure how it will respond to variables 'J' or 'K' for J-integral and stress intensity factors respectively.

Characterising fracture toughness in epoxy using mechanical fatigue. Help!

Hi all,

I have taken up this research project/attachment on
"characterising the fracture toughness of epoxy using mechanical
fatigue", and encountered lot's of problems while researching. I'm just
a student, not even in university, but rather still schooling (grade
10), so am completely new to this field, which explains my problem in
understanding all the lit reviews, lecture slides i found online.
Luckily, i found out this site, and would hope that someone can guide
me in the right direction!

FRacture Growth - Abaqus Explicit

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Hi,

        I want to model 3D crack propagation in Abaqus Explicit. For this I am thinking of using the *shear failure option with element deletion. The path of the crackin my models is not known. I have some basic questions in this regard.

 

1. Is *shear failure a good approach to model crack propagation ?

 

2. I am modeling crack growth in geological materials. Usually cracks propagate in the trail of a damage zone. Can this (damage zone) be reproduced in Abaqus Explicit with *shear failure option ? 

Thanks in Advance,

Fundamental solutions in anisotropic plane elasticity

 My problem is the following: I have a bounded domain \Om in a plane, and I am looking for the fundamental solution

div_y C \nabla N (x,y) = \delta_x,    in \Om

where C is the elasticity tensor (anisotropic),  with natural Neumann boundary conditions on \partial \Om (traction free).

 I don't ask for explicit solutions! I would like to know that 

  \nabla N(x-y) \le C/|x-y|, where C is a constant depending on whatever!

 

help for determination of crack initiation location with analytical methods

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  There are three elliptical holes in the given plate, but make different angle with the direction of stress applied on the plate. I wonder if I can gain the solution listed below using analytical methods?(1) crack initiation will happen in which ellipse firstly, (2)the exaxt crack initiation location around the ellipse? And how?

 

thanks a lot!

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