Best way to mesh thin hollow tubes and solid bodies in the same assembly

Hi guys,

I am designing a boiler which is fairly big. (14m x 8m). As you might expect the tubes in the heat exchanger are thin (compared to the whole model). I am trying to apply a force to shake/remove dust from some tubes , and I am only interested in stresses in connections and displacements at the end of the tubes.  My problem is that if I run the model as a solid the mesh density gets too fine , It will run for a day or more without finishing the study, eventually freezing (No warnings, sometimes solidworks crashes/freezes, computer specs i7 4770k, 24 gigs ram, k2000 gpu). I have already used shell and structural members for some of the tubes/bodies in the assy, but my problem is that the model also contains solid bodies. When I try plotting stresses and displacements I cannot see both types of bodies at the same time. Is there a better way of accomplishing what I am trying to do? I am running out of ideas. I have added a jpeg of the assembly.

Best regards,

Arkmando

SolidworksSimulation