HOW TO MAKE THIS PART IN SHEET METAL?
WHAT ARE THE WAYS TO MAKE THIS COMPONENT USING SHEET METAL FEATURE AND TO FLATTEN THIS TO KNOW THE BLANK LENGTH REQUIRED?
this part can not manufactured by standard sheet metal tools. you need a die to make it . you need some add ins to modeling die like quick press. such add ins have automatic blank calculations for you.this would be the best way to blank calculation because you will have different thickness in order to strained regions!
Ok, I should explain it with screenshots, my fault.
Answered with a tutorial: https://grabcad.com/tutorials/how-to-make-this-part-in-sheet-metal
This cannot be done with sheet metal tools directly. One way to do this is to draw the profile with small straight lines in order to create bend lines. If you only need this for calculating the required material you can open a sketch on a plane in the center of the part, draw the inner profile using convert entities and then use the measure tool.