Sol101 vs Sol106 membrane forces f06 output inverted axes

[albertoruenes]

Hi all,

I'm working with some linear(101) and non-linear(106) models to extract membrane forces from composite structures modelled via pcomps.

As the membrane force direction matters for the post-process analysis(i.e. using the f06 loads i calculate stresses and strain for the composite out of Nastran) in the direction of the principal axes.

For linear solution the membrane forces in the x and y direction are very similar to the membrane forces in the y and x (i.e. inverted axes).

Do you know if this is a common case in Nastran and if there is any way to prevent or know which orientation is the correct between linear and non-linear?

 

[albertoruenes]

Just in case anyone look into this,

I was using for the linear solution the param,omid,yes card which is only valid for linear, as the element coordinate frames happens to be 90 degrees phased from the Material coordinate system i was getting these "inverted" results.

 

[Tuw]

Hello albertoruenes,

What output request you used to recover membrane force?
If you use force output, the output is with reference to the element coordinate system. If you are doing automatic meshing, the element coordinate system would be in chaos, thus high chance that the axis are not consistent.

Kind regards,
Tuw