hi everyone,

I am trying to model and simulate Fatigue crack growth for a cracked plate emanating from a rivet hole.

Loading: constant amplitude loading upto Kcrt reaches

Fem Method: XFEM

Following is the meshed model prepared for XFEM analysis

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1. İs it required to define local coordinate system at crack tip in XFEM method?

2. Even in SING method I cannot define my crack tip inside an element, why?

3. In order to constant amplitude loading I follow the following ,

time, 1.0

deltim, 0.02, 0.02,0.02

while

CGROW, FCG, METH, LC ! life-cycle method

CGROW, FCG, SRAT, 0 ! stress-ratio

!loading frequency is 25 Hz

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Does the abovementioned strategy true?

4. How I can monitor cycle by cycle crack propagation and related crack parameters (a, deltaK and N)?

5. Crack front node number mentioned here does not listed in APDL node list call; is this a virtual node produced fro XFEM?

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6. By changing the loading magnitude and frequency I always get the following graphic. There is no change in the amount of crack growth (graphically).

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your helps and comments are fully appreciated in advance