Point support moves

mmm, I’m trying some sort of shell analysis and there are some issues…Please help.

  1. it seems like the point supports moved.
    Below image is 10x magnified deformation. (Also the adjacent surfaces do not seem to be aligned correctly.)

  2. The principal stresses do not appear symmetric. Although everything was supposed to be symmetric in the original model.
    Annotation 2020-05-19 152942

Please help :sweat_smile:

Can you post the GH-file?

Here you go. The geometry is internalized. I hope it should be an easy fix…
kiwi3d.gh (228.7 KB)

Thanks in advance!

I had a look at your file: The problem with moving support is easily fixed. We use springs for the supports and you have to apply higher spring stiffness. This can be adapted by right-clicking on the AnalysisModel and setting the penalty factor to a higher value (I added two zeros). This improves the coupling between the patches as well. Then simply update this component by newly connecting a wire upstream.
Regarding the forces, this is also related to the supports. Since you are using point supports, the support is only added to one patch where then high force concentration occurs. Line supports of small lengths are typically better for shell analysis without edge enforcement (as in classical FEM) if the region of the support is important in detail.

Thank you Anna! It is very helpful!

a question regarding the opposite case: If I do want my support (point and curve support) to have a low spring stiffness while having a high penalty factor for strong coupling, my code is the following:

Would that be the correct lines to change?

yes, those lines but this woks only for point supports. And you have to uncheck ‘strong support’ in the support component. For the curve supports, it is a bit more complicated. You have to copy and adapt the property of the edge coupling:
and set a free property ID. Then you have to filter the lines under DE-BREP-NURBS for non-coupling lines and set the third number to your new property id.

How do I uncheck ‘strong support’ in the support component?

Regarding curve support:
With ‘non-coupling lines’, do you mean in the picture below the first two lines (I thought that they are related to point support) or the latter ?
DE-EL 3 has curve and point support (DE SUP ID 1+2). If I connect the curve support component with support I do get EL-PROP 4 : NURBS_BREP_EDGE_COUPLING in the input text, but in DE-BREP-NURBS there’s no line with property ID 4

you just have to rightclick in the middle of the component and uncheck it in the menu.

Ok, in your case they are related to the point support. But if the curve support is applied to a surface, there might be lines that have the same property (third number, here 6) as the edge coupling. El-Prop 4 is not used as strong supports are applied. You can see this in the DE-SUP lines. If there is no DE-BREP part, it#s a strong support.

Okay, thanks. Unfortunately, there’s no menu when rightklicking on the support components like there’s one for e.g. at AnalysisModel and IGASolver. I already did a new installation of version 0.5.0, in the existing example files there’s also no menu. Is there another way to make it a ‘weak’ support?

Ok, sorry, this feature is part of the new release.
You can also manage this in the textfile. Instead of describing the location with u=0 in DE-SUP you can also do it with a line in DE-BREP-NURBS. You can find more information here:

However, there are only strong suppports at the end of a curve. If you move your point slightly, you’ll get automatically a weak support. For supporting a whole curve, just split the curve input of the support component into two parts and it will also use weak supports.