Hello, I loaded a “hand” prepared ccx file into cgx and I got the following error for pressure loads on a set of shell elements:
ERROR in seta: A negative entity-index:-1 was used in set +dlo
Any hint about why it could happen?
Thanks.
Hello,
maybe you have to flip your surface !?
the error appears only with dload ?
wbr dichtstoff
Hi, thanks for answering. I created a simplified example of my actual problem with all surface normals external to the box, however I get the same message…
I attach a linke to the .inp file in case someone has the time to have a look.
Hello,
it is always good, to use different version of CalculiX.
With CalculixLauncher i get these error:
ERROR in set:+dlo, face:2 of element:4127 does not exist.
…
ERROR in set:+dlo, face:2 of element:5126 does not exist.
i think these is one surface / area of your box !?
all other areas / surfacesa are working ?
maybe it is a problem of your model with meshing ?
wbr
I checked with Ubuntu version (installed from repository, means v2.13) and same result…Using launcher for windows cgx v2.5 it casts no errors, however +dlo set is empty, v2.10 same as you “ERROR in set:+dlo, face:2 of element:5117 does not exist.” this for all shell elements I guess…using v2.16 I got again the error: “ERROR in seta: A negative entity-index:-1 was used in set +dlo”
I’ll try later with launcher under linux…
The fact is CCX solves it without errors and results are physically fine.
The error changes with the version but it’s still there. I can’t find any issue with the inp file. Also I found that despite the shell normals pointing outwards (see picture
) and load being suction I have to set a positive value in the DLOAD card (cara_inf,P,0.001) despite CCX manual saying “For shell elements no face number is needed since there is only one kind of loading: pressure in the opposite direction of the normal on the shell.” (page 453 of v2.17 manual) as you can see in the deformation plot attached .
However I do not think this can create the problem…
I have created another model with only 3d elements, here I do not get any error. +dlo is filled with all faces where pressure is applied. I believe that the problem is due to having a solid core plus outer shell faces in the original model; that is not well digested by cgx. I do not know if this is an intended behaviour or not.
In the link the 3d only model: https://drive.google.com/file/d/1f1aQL5zqej0wORW8Fi9wgEghxJ2Aok_u/view?usp=sharing
the CGX manual says in p.9 “It should be noted that faces exist only on free surfaces of the model.” and when the model is solid element plus a layer of shells what you get when you plot the faces is the following:
That means that no faces can be selected in the overlapping regions to apply pressure loads and that that has to be done directly in the .inp file as far as I understant it. It cannot be created directly with send command.