Numerical singularity error

[Serbu]

I am trying to simulate a wind turbine model in abaqus but every time i try to run the job, the numerical singularity error shows up. I simplified the model to only have a blade and the nacelle (2 parts overall in the assembly) with the blade connected to the nacelle through a bushing connector (simulating the bolts). I applied a pressure distribution on one side of the blade to simulate the lift experienced by the blade and fix the nacelle with an encastre. I tried to apply more boundary conditions but the system gets overconstrained and although the jobs gets completed, the results are not saying much. Do you have any advice?

 

[FEA way]

Numerical singularity is just a warning (usually occuring in undercostrained models). Are there any actual error messages ?

 

[bkal]

Apologies if I misunderstood you, but is your blade free to rotate about the bushing connector? Could that be a problem?

 

[Serbu]

Numerical singularity is just a warning (usually occuring in undercostrained models). Are there any actual error messages ?

Due to numerical singularities the solver can’t solve the iterations and at some point after five unfinished solver tries it aborts the job automatically.

 

[Serbu]

Apologies if I misunderstood you, but is your blade free to rotate about the bushing connector? Could that be a problem?

Well i thought about that and i put a fixed constraint at the other end of the blade and the solver completes the job but the results are not saying much ( cause now it s fixed at both ends basically). Do you have any ideas what constraint or boundary condition to put to fix that rotation?

 

[bkal]

Well i thought about that and i put a fixed constraint at the other end of the blade and the solver completes the job but the results are not saying much ( cause now it s fixed at both ends basically). Do you have any ideas what constraint or boundary condition to put to fix that rotation?

I guess it depends on what are you interested in. If it is stresses in the blade, I would start with fixing rotation in the bushing. Have youlooked inte an example from Abaqus manual: Analysis of a rotating fan using substructures and cyclic symmetry