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FATIGUE CRACK PROPAGATION-- ITS IMPORTANT

Submitted by Amit S. Kulkarni. on
research

[img_assist|nid=8803|title=FATIGUE CRACK PROPAGATION-- ITS IMPORTANT|desc=|link=none|align=left|width=100|height=63]

 

Hello,    

          Currently , I am working on the fatigue crack propagation in ANSYS 12.1. Can anybody help me regarding how to get the next cracktip position?
Currently, I am referring to the paper named, “Mixed mode fracture analysis of aluminium repaired panels using composite patches” , Authors : Hossein Hosseini-Toudeshky, Bijan Mohammadi, Hamid Reza Daghayani.

According to this paper, I am using following two equations for calculating the incremental angle of crack propagation (α) :

Please Refer Images

 

But, I am confused in which direction does I have to take angle α , i.e. in anticlockwise direction or clockwise direction with respect to the X-axis of the local co-ordinate system at the crack tip? Please Help me if anybody knows about this.

  

 

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Imechanica Query.doc 139.5 KB
Reza Talemi

Hi Amit,

I am working on Numerical modeling of crack initiation and propagation in fretting fatigue as my PhD project, and I am using APDL for this purpose.

In order to propagate a crack in ansys with apdl you need to fallow below steps.

1- Modeling the problem without initial crack and seeing the results and stress contour to find the best place for crack initiation  

2- Modeling with crack and modeling stress concentration at crack tip in order to find KI and KII at crack tip( there are different ways to approach this)

3- Finding the next position of crack tip and crack orientation that sign of KII will govern the wright angle of orientation( there are also different criteria for this goal)

4- Remeshing the area that is contianing the crack tip.

...

Also each step has a lot of details in the APDL that needs works to go inside of the subject.

Anyway, I am working to develop a code in order to model the crack propagation in fretting fatigue phenomena. and I have some resource for it, if you are interested please be in contact with me with below email address.

reza.hojjatitalemi [at] ugent.be

Best Regrads,

Reza 

Fri, 09/17/2010 - 20:30 Permalink