Wind turbine hub calculation in Ansys

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Animated FEM deformation plot of a wind turbine hub in Ansys
Deformation of the wind turbine hub under extreme load

Some will already know the wind turbine hub model, but now I have taken the time and remade the model in Ansys Mechanical. At the latest, the following animated image should bring back memories of “Wind turbine hub calculation in PrePoMax“.

Wind turbine hub with FEM Equivalent Stress in Ansys Mechanical window
Wind turbine hub with Equivalent Stress in Ansys Mechanical window

I am surprised how similar the deformations and stresses are, although a completely different mesh was used. Furthermore, I have changed the fatigue.pro label so that this area is now more softer.

Comparison of Deformation and Mises stress of a wind turbine hub in FEM PrePoMax and Ansys
Comparison of Deformation (left) and Mises stress (right) results from PrePoMax (upper) and Ansys (lower)

The new mesh in Ansys is a full Hexaeder mesh (Hex20 & Wedge15 only) with 1.31 million nodes and 267984 elements. In PrePoMax was used a coarser full Tetrahedron mesh with 1.4 million nodes and 810054 elements (see “Wind turbine hub calculation in PrePoMax“).

Mesh comparison of wind turbine hub model with hexaeder mesh created in Ansys on the left and Tetraeder mesh created in PrePoMax on the right side
Hex mesh created in Ansys (left) and Tet mesh created in PrePoMax (right)

How is it possible to create such a hex mesh in Ansys Mechanical. Following video showing the steps to build up the model. You find more details of the model and the used loads in “Wind turbine hub calculation in PrePoMax“.

Ansys Mechanical simulation quick run with wind turbine hub
Ansys Mechanical simulation quick run with wind turbine hub

When we compare the stresses in detail, the depth of the fatigue.pro label and the influence of the fineness of the mesh become more noticeable. So we can see slightly lower stress values at the hole edge. I am curious what the results would look like with the Ansys mesh in PrePoMax. Maybe I will port the Ansys mesh to PrePoMax in the future.

Mises stress at half wind turbine hub and a mesh detail from PrePoMax (upper) and Ansys (lower)
Mises stress at half wind turbine hub and a mesh detail from PrePoMax (upper) and Ansys (lower)

In the following animation you can check how the stress in the wind turbine hub is changing during rotation.

Wind turbine hub with FEM Equivalent Stress rotating in Ansys Mechanical window
Wind turbine hub with Equivalent Stress in Ansys under extreme load

Even the full wind turbine hub model shows a good stress distribution. The very simplified bearing model have some high stress and needs a more realistic nonlinear model. And even preloaded blade bolts would change the stress results in that area.

Full wind turbine hub model with FEM Equivalent Stress rotating in Ansys
Full wind turbine hub model with Equivalent Stress in Ansys

I have already calculated many such models with Ansys, so I just want to show the procedure in the software and the results. And for me it is still impressive how close the results with PrePoMax are to this calculation.