Sorry about the confusion. Roof bows. 3m VHB tape I'm not familiar with it.
It is a Very High Bond double sided tape made by 3M. Commonly used to attach modern trim and emblems. Also used on smooth side (rivetless) enclosed trailers. The large sheets of smooth fiberglass or aluminum are secured with this tape to the frame structure.
The bows are secured at the edges as Scoop said, but when they get distorted from someone getting on the top or similar, they sag below the skin of the roof and rattle.
If you can carefully pull them down and wedge them in place, then clean off both surfaces and place tape on the bow, you could then push it up against the skin to secure it and prevent any rattles. Make sure you have it clean, and lined up right, it is a bitch to re-position, and after it sets for a day or so, it is there for good!
You can get it at McMaster Carr, but it is pricey. I have seen rolls of it on ebay much cheaper. Just search for 3M VHB tape and a bunch will come up.