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Fracture Mechanics Forum

Starting out question

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Hi

This is my first post so bear with me.

I have a question and an answer but have little idea how they got the answer.  The question relates to a sample with load being applied at both ends.

Question

mathematical equation for a crack in a ductile material

hi all,

im an engineering student...im doing a project on crack behaviour in a ductile material(mild steel) when a load is applied on it...im going to analyse it using ANSYS, for validating this i need a mathematical equation.....so plz if you have mathematical equations and journals regarding it plz reply me ...thank you...

 

sabarirajj@gmail.com 

 

Literature regarding the appearence of cracks in steel. Thermal, pressure fatigue

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Hello!

I am wondering if anyone could recomend som literature for me to get my hands on.
If there is any literature regarding how the appereance of a crack in a piece of thin metal (~0,5mm - 1 mm) could be related to pressure fatigue or thermal fatigue.
Does the crack due to thermal fatigue have a specific appereance and so on. I need get my hands on practical pictures and so on, not equations.
Are there any signs in the vicinity of the crack that is indicating that this could be due to pressure fatigue.

Any help is much appreciated.

Thanks

3D modelling of an ellliptical crack in ANSYS

I am a beginner in FEM and just started using ANSYS.  I need to study the stresses and SIF at the crack front of an elliptical crack inside a material subjected to a stress perpendicular to the crack plane.  Any details on how I should build my model?  

What is the easiest way to define a cracked area, and crack front and then mesh it

How can i merge together a cracked area and an unmeshed area? 

I found a lot of links and articles that states they did it, but none explained the procedure do do it. 

 

Thanks 

Pooyan's picture

Failure Criteria

Hi

I want to know in Ansys software, what are the failure criteria values for steel in picture below?

 

Failure Criteria 

 

Regards

 

Pooyan

How to plot J-integral path

Dear all,

I am a new Abaqus user. My work involve with fracture modelling by using Abaqus.

I model 2D-Edge Crack problem by using Abaqus. For the output, I request 5 values of J contour integral at the file history output, and Abaqus provides me 5 values of J - integral. However, I can not plot the J-integral path (J - integral versus Radius). I know abaqus will choose the path of each contour integral automatically. But I don't know how to show the path of each contour integral.

 Could you please suggest me how I should do.  

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 

Haroon'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?

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