converting solid part to shell in geometry of CAD is available but all face still connected as single parts. The purpose of converting to shell from solid usually using mid-surface, not a group face of hollowed closed surface or solid. The limitation of mid-surface is not really problems and still usable since CalculiX shell element have offset feature, thicken shell to generate solid element is available in PrePoMax also. However it’s required an option to separate faces by explode or detach all face, so it can be merge by compound later.
Yes, but that’s much more complex to implement so the basic hollowing was added. Abaqus also has it.
However, this is easily doable in CAD software - e.g. Draft Downgrade and Upgrade (or not to keep separated faces) in FreeCAD:
regarding midsurfacing, may the condition is different in the future and PrePoMax capable todo since current versions can detect edge length of thickness during extrussion.
right, it may easy and doable in CAD to explode a solid into group of closed surface. As another thread discussion, user expect to delete or define merge of face group by selecting individually to complement of convert solid to shell feature. It seems this operation is more convenient inside PrePoMax.
The Solid to shell feature was added because the feature shell to solid was needed for some cases. So it currently has no practical use. A feature to delete shell faces is missing to make it at least practical for the thickened shell mesh.
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thanks, explode first when converting make face of shell part separated individually and delete is accessible through menu trees.
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yes i also noticed the same yesterday.
Does know somebody the trick in Inventor to create from Solid a Shell Element with the mid surface?
Autodesk should have such a feature within its simulation tools (Simulation module in Inventor or Inventor Nastran). Otherwise, you could use the surface offset tool: https://www.youtube.com/watch?v=HYBRaSR7nVk
I do it in FreeCAD, but it’s a manual approach.
midsurfacing for common FE software with classical formulation is mandatory to avoid additional moment due to eccentricity, but CalculiX ignoring offset condition make it less complex since outer/inner surface can be used directly.
Abaqus has both offsets and real shells and here’s how it works there:
The degrees of freedom for the shell are associated with the reference surface. The element’s area and all kinematic quantities are calculated there. Any loading in the plane of the reference surface will, therefore, cause both membrane forces and bending moments when a nonzero offset value is used. Large offset values for curved shells may also lead to a surface integration error, affecting the stiffness, mass, and rotary inertia for the shell section. For stability purposes Abaqus/Explicit also automatically scales the rotary inertia used for shell elements by a factor proportional to the offset squared, which may result in errors for large offsets. When a large offset from the shell’s midsurface is necessary, use multi-point constraints instead.