Hi,

I am performing an XFEM fatigue analysis using the *Fatigue step.

Using a coarse mesh (element size 0.2 mm) for a part of about 5 mm thickness, the simulation runs fine.

However, refining the mesh (element size 0.1 mm) causes this error which terminates the analysis:

THE SYSTEM ERROR IN STD_FINDCUTSHAPE3D8_XFEM -- NODAL LEVEL SET 
VALUES MIGHT NOT BE CORRECT FOR ELEMENT 53265 INSTANCE TEST-1, ITS 
PHILSM ARE 3.84511E-03, 1.72150E-02, -0.17324, 1.38014E-02, 
-2.31634E-03, -3.38051E-03, 0.14667, 0.14347.

Visibly, the crack at this location starts to deviate from the horizontal plane and begins growing vertically. The 1st simulation with the coarser mesh predicted a purely horizontal crack plane.

Furthermore, the fatigue life predicted using the fine mesh (before the error occurred) for the crack to reach a certain area is much longer than that predicted using the coarse mesh for the same crack area.

Does anyone know what is causing the error for the refined mesh and the different predicted fatigue life?

Any help is much appreciated!

Abaqus ​​​​​​​