Mesh a helical surface gives warping quad

Hello all, I’m a new user of Salome Platform. I created a helical surface structure using Geomety module and I want to mesh it. For that I create a mesh with Quadrangle Mapping 2D algorithm and Wire discretization 1D local segment. I wanted to know if I can avoid the warping phenomenon.

This warping is reported by CODE_ASTER analysis as a potential source of error.

Any help is welcome.

Thanks you

Minh-Huy

If your elements are second order, you could try turning off the mid node on geometry.

Hi Sergio,

They are first order. What do you mean by turning off the mid node on geometry? I used “Geometry” module to do the geometry to mesh.
Thanks you!

When you generate quads elements, as far as I remember they are generated as first order quads, so you can convert to quadratic using the specific tool. There you have the option to put the mid node in the geometry (more accurate representation of the geometry, but leads to curved elements), or in the middle of the two nodes, so will be a flat second order quad.

image

So we need to have quadratic elements. Anyway both option with mid nodes on geometry or middle of two nodes erase the warping completely!
As I need to export to NASTRAN format so, I need to check if we can use quadratic elements first. This is another story.

Thanks you very much for your time.