I am doing propagation life calculation of gas turbine disc under fatigue loading. I am doing this in ansys. i modeled surface crack in the model and calculated stress intensity factors k1,k2,k3. According to theory, kink angle sholud be calculated for each node on crack front using k1,k2,k3. after that, non planar crack should be modeled in the model with new crack front nodes. I think that is very difficult in ANSYS. So, can i use planar crack growth while using resultant sif calculated from k1,k2,k3 in paris equation ?? how much difference i will get in life if i use planar crack growth instead of non planar crack growth in mixed mode loading ?? if possible, can any one provide experimental result of life under fatigue in mixed mode ??
Very Interesting question, similar to my case. Could you check one of the spesial journal in .... (lets me check first....)
Hi Zol, can you please share with me that what you found on this question ??
yes you can use, however u need to find k1,k2,k3 from critical plane approach
Thanks Nani,
what is critical plane approach ?? can you please provide any reference for that ??
I hope that this paper should be very useful - see details of the critical plane position calculation.
http://link.springer.com/article/10.1007%2Fs10704-005-1088-2
Hello friends,
I am doing a project on crack growth simulation. I have determined the stress intensity factors k1,k2 and k3 of a plate with an initial crack using ansys. Could you please help me how to implement crack growth simulation in Ansys.
Please help with your valuable comments
Note: Am using shell181
You can mesh the crack using Patch Confirming Method having Tetrahedran Mesh. Also I personally suggest you that meshing of crack surface depends on type of crack you are providing.
Good question!
I believe that, if DKII and DKIII are small in comparison to DKI, it is reasonable to assume that the crack grows in a plane. This happens because the "first mode of opening" is dominant.
If this is the case, you can just neglect DKII and DKIII and just employ the DKI in the Paris equation to estimate the crack growth increment.
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