Couldn't find any specifics on this but I don't really know where to look.
In cases where an impulse is applied (like from a spacecraft docking) or some kind of vibration (perhaps from a reaction wheel) excites structural vibration in a vehicle (specifically structural because the damping tends to be low anyway), how do these modes decay? Specifically, where does the energy go?
In atmosphere and on the ground you could say that the energy decays into sound (For instance, if a drum gets hit) and/or heat from friction, but assuming a linear elastic model for common structural materials (which is where I guess there's an issue here) you wouldn't expect this to happen in a vacuum and isolated from the ground.
My best guess is that it decays by hysteresis within the material, eventually into heat, and eventually radiated out, even if the internal stresses remain below yield-otherwise I don't see anywhere else the energy could go.
Thanks for reading (And also please tell me if I should post in another section).