Fracture Mechanics Forum

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

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 

The size effect in fracture is an important topic in fracture toughness. However, when we measure the fracture toughness of ductile materials, the standard specimens in ASTM E399 are usually adopted. I find there are few experimental data with different specimen sizes available for single notch bending test, so dose somebody provide some clues or hints for this kinds of experimental results? Thank you very much!


Reza Hojjati's picture

Using ABAQUS *.inp file in ANSYS

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? 


Hcham's picture

crack progagation whith XEFM

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
*DAMAGE INITIATION,CRITERION=MAXPS
8.44E7,
*DAMAGE EVOLUTION,TYPE=ENERGY,MIXED MODE BEHAVIOR=POWER LAW,POWER=1.0
4.22d4,4.22d4,4.22d4
*DAMAGE STABILIZATION


numerical modelling of orthogonal machining

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 ??

hello all


mmaaa's picture

fracture mechanics plus matlab

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

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

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.

If we define the limit load as a collapse load, the material collapses only when the flow stress is reached. In this way, we have to set the inflection point of the elastic–perfectly plastic material on the flow stress, which sometimes is asumed to be (1/2)*(Sig_y +Sig_m). [Sig_y: yield stress, Sig_m: tensile strength]


Reading contour integrals from Abaqus output database

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.

I am quite new to script writing and hope someone could share their expertise. Find my attempt below.


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

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,

GSR

  


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!

 

This is relevant in the study of the stress near a dislocation. Indeed I know the solution in all the plane, and I know how the stress decays in the all plane. I need to estimate the stress if the domain is bounded (how it is!!!)


help for determination of crack initiation location with analytical methods

  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?


Strain Based Fracture Mechanics

Hi!

Can anyone give me some tips within strain based fracture mechanics. My problem is predicting the fatigue life of a gusset speciemen, using strain based FM. I have read some litterature, but have problems on understanding the order of calculating, and methods of solving the equations. If anyone could help me understanding, I would be greatful.

Thanks,

Sean Angus


Crack propagation using VCCT in ABAQUS

Hello,

I am expected to calculate strain energy release rate for a single lap composite joint using VCCT in ABAQUS.How do I go about it?

The manual saya some thing about debonding? How do i do that in my model?

Thanks,

Srilatha

 


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