hyper

1) why geometry cleanup operations r required?

ans: The gaps, overlaps and misalignment's that can occur when surfaces are
imported into HyperMesh can prevent the automesher from creating quality
meshes. By eliminating misalignment's and holes and by suppressing the
boundaries between adjacent surfaces, you can automesh across larger,
more logical regions of the model and improve overall meshing speed and
quality.

2) how to connect shell and solid elements?

ANS: Two options one has in connecting a solid to a shell
first option: Overlap some rows/columns of shell elements with that of
solid elements .with the fact in mind that only there are overlapping
DOFS corresponding to the three displacement components. There is no transfer
of rotational components. This is justified in that the displacement DOFS
being apart by a distance of length of element account for rotation components
coming in.

Second option: Is by penalty function approach, although u can have a rigid
spring with high stiffness to transfer the displacements.The solution all
depends on what kind of load transfer that is expected between the solid
and shell. If join is assumed to be rigid and with the external loading
causing no much predominant twist at the joint the use of above two options
is valid.