Problem drawing a twisted wing

[Leo44]

Hello,

I'm having trouble drawing some wing profile on Abaqus. (note: i don't have access to other software such as Catia or Solidworks, only Abaqus 6.12.2)
I intend to draw a wing profile, with complex curvature and some twist in it.

I wrote a python script to generate different section of the blade

Note that the first and last are actually shells, the inside ones are wires.

Another view

My plan was to wrap all those profiles with a loft shell. I almost get a perfect result except for some nasty wrinkles due to twisting.
Here is what i get :

I don't get those wrinkles when i don't twist the wing.
But i really don't know how to get rid of them and obtain a smooth shell.

Should i use another method ? Or is there a more accurate tool than the "Loft" ?
I'm new to abaqus so i might not have seen an obvious solution.

Thanks for the help !

 

[corus]

Post the cae file and someone might be able to fix it.

 

[Leo44]

Here it is.

 

[Leo44]

I'm going to try to create two separate lofts, one for the upper surface and one for the lower surface. It might avoid this turbulence area where wrinkles appear.
I'll see how it goes

 

[corus]

I tried different methods of reducing the problem down to loft sections between each strut and partitioning to obtain structured regions but the meshes produced were all bad where the elements didn't appear to follow the surfaces regardless of the element size. The problem seems to be the trailing edge with the small curvature there. Abaqus doesn't like these spline curves at all and can't seem to manage such changes in curvature. I'd try and get the original geometry and draw it out properly with defined radii. If not possible then perhaps omit the small curvature completely and simplify it by having the trailing edge just ending at a point.

 

[Leo44]

Thank you for the advice.
I think i'll just let the trailing edge with a pointy ending, and then make another local model just to study those edges with more precision.

 

[corus]

Sorted it. I split the loft sections into 3 regions, separating off the small curvature at the trailing edge of the wing. As an example I chose just the last section, at the wing tip, and suppressed the remainder of the structure. These bits could be added in later using the same method. I've attached the cae file but it is in 6.13 version so I'm not sure if you'll be able to open it. I've also attached a picture of the mesh and the part showing the 3 lofts used to mesh it.

 

[corus]

Here's the cae file but I removed the mesh to reduce the size of the file.

 

[Leo44]

Thank you very much !

I can't open the file unfortunately, but i get the method.

 

[Leo44]

Actually I guess I could use the .jnl file, right ? There must not be so many difference between the 6.13 and 6.12 versions.

 

[corus]

Here's the .sat file you can import as a part to see how it's been partitioned.