How to modeling the dome part to bent manufacturing method?
How are you planning to "bend" it?
The part you shown need to be "form". Using press and die. It is not a "sheetmetal" bend part.
So "bend allowance" or "k-factor" in sheetmetal will not work.
Something like that I would do as and Extrusion of Pipe then add the dome end with the dome feature. Or as a solid then shell it. Bunch of ways.
The Design that you show is made using the "Metal Stamping Process", this is not a Air Bend part, which is what SW helps figure out..
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