I have very basic level question: How connect shells in prepomax? shells have different thickness so can not be made as compound (connection edge to edge or edge to face in T joint connection) .Some more complex tutorial would be a great help in this area.
best regards
Tie constraint or (better) merging to create a continuous mesh should do the job. Some overlap of the material might be unavoidable but itâs commonly encountered and usually ignored (results are read away from the connection). However, you can try using the offset option in the shell section settings to model the connection more accurately, with no overlap.
I think that the compound part should do the trick. Then you have to assign different shell sections to different part faces.
ânot exactly since it creates one shell part (easy to mesh) , but I want to keep different thickness for single shells after compound it is impossible
best regards
the surface of a part need to partition before in CAD youâre using. so different part of shell properties (i.e thickness, offset, material) require to be separated.
*edited (addition)
in case of shell with single part, only at specific geometry can be selected base on mesh and angle criteria. for example multipart tubular steel, selection of chord, brace diagonal and vertical member are possible.
This appears to be an older topic but faced a similar issue recently when trying to model a double lap joint of 3 composite plates. Using the âThicken-Shell-Meshâ option for meshing worked just fine as effectively solids are created which can easily be connected using constraints. However, issues arise when using the Calculix Keywords to create layered composite panels rather than expanding the shells to solids. This is the set-up of three surfaces created in FreeCad:
In this scenario, it is straightforward to apply a (tie) constraint to the shells (surfaces) touching representing the centre and one of the lap joints. However, constraining the other âfloating shellâ to the centre plate appears more challenging⌠It took some time, the automatic search for contact pairs obviously does not work but also the âdefaultâ tie constraint settings of PrePoMax caused errors when used. However, mimicking the automatic search settings of âSearch Contact Pairsâ used for the touching shells also for the âfloating shellâ worked well and the model appears to run.
There still seems something not entirely correct as the displacement should be symmetric which it is not but will check my settings again (yes, have tried for a while but probably need to sleep a night over it ;)âŚ
Anyhow, hope this description of how to connect shells with different thicknesses helps someone else (even if not a T-joint ;). Here the pmx file (I used v2.2.11 dev) in case of interest:
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