Thanks a lot.

A couple more questions please.

1. The geometry of the pipe and metal base is very complex. I had to greatly simplify the geometry of the pipe, remove the holes on the flanges, simplify the valves, remove fasteners and chamfers and fillets on them. I made the pipe a single body in the space claim. I set the mass of the sliders through point mass in order to save the masses after changing the geometry. Is this allowed? Will this affect the accuracy of the calculation? Th frequency modes will not change much.

It was like this

it became so

2.  How else can you forgive geometry? I ended up with 500,000 grid items. I have a powerful PC, 8 cores, 32 GB of RAM, but this is not enough, a memory error appears. I tried virtual topology, it didn't help either.