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Hello Sean,
In this figure, when we say that ‘k models the stiffness of the water tower structure’ and ‘c models the inherent damping in the water tower structure’, actually we are stating the below facts ;
1- Water Tank Structure is only considered as a mass because it is filled with water totally, and negligible for consideration of stiffness and damping calculations. Just a mass
2- Therefore, actually k defines the stiffness of the water tower and c is the damping coefficient/ effect of solely the water tower. (water tank is ignored.)
Is that the correct interpretation ?
Cheers
Burak
Hey @m.burakcakir33,
Sorry about the delay in replying to this - we had a technical hiccup which means I haven’t been receiving forum updates for about two weeks. It’s fixed now but I’m working through a bit of a backlog!
Yes, I would say that your two statements are correct - the stiffness and damping of the SDoF dynamic system could be almost wholly derived from the structural configuration of the tower, less the lumped mass (water tank on top). And, since the majority of the mass is concentrated in the water tank, it’s reasonable to assume a single lumped mass as a model. With this approach, we may or may not neglect the mass of the tower.
Keep in mind, this is a relatively crude simplification of the water tower structure. In reality, it will have several significant modes of vibration - but the presentation here is really just to demonstrate the link between a real structure and an approximate dynamic model of that structure.
Seán
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