hi,
beam & shell element are expanding to solid element in CalculiX during calculation. bellow are an explanation i extracted from official documents, may apply to beam element also.
- Shell element S4 expanded to solid C3D8I: cannot be used in *DYNAMIC calculations, has controlled hourglassing, (ed. still questionable for one layers only)
- Shell element S4R expanded to solid C3D8R: small elements are required to capture a stress concentration at the boundary of a structure,. massive hourglassing, displacements are completely wrong, but stress field is still correct.
- Shell element S8 expanded to solid C3D20, badly for isochoric material behavior, i.e. for high values of Poisson’s coefficient or plastic behavior. too stiff in bending
- Shell element S8R expanded to solid C3D20R: high stress concentrations at the surface of a structure might not be captured if the mesh is too coarse. problems in node-to-face contact calculations
- if the user manually define layer by duplicated mesh with offset options, it will generate knot for every nodes and deformations result may lead to be too stiff
since beam element B32 expanded to C3D20 so the performances are probably bad for plasticit behavior as mention above…
best,