here is a dummy model, plate on the left side is midsurface and on the right side kept as solid (bcz not possible to create midsurface in actual model) these two plate are connected by some screws. so now to connect these model i am thinking that i can have three approaches , first very conservative that is bonded whole contact area, second is beam connection and last comes in mind is fixed joint , I have solved modal analysis for all these ( that is what i am performing on actual modal) and found following result.

Can you please suggest which approach i should select, i dont want to use 3d bolt or screw.

 Fig. Geometry

fig . Mode 7 with beam connection

Fig . Mode 7 with Fixed joint ( fixed joint is created between the edge of the holes on midsurface and internal surfaces of holes in solid plate)

Fig. Mode 7 for bonded contact on both the surface which are in contact

as we see the bonded contact having high frequency which  should be, while performing this bonded contact approach i also came across one warning which i dont know how important when i will be perfoming modal analysis of actual modal which has lot of conatct element in shella nd solid bodies.

Warning messege 


(my original model is an enclosure which is having all the solid plates screwd, but due to complexicity few plates are not possible to midsurface and i am performing a modal analysis)