SOLIDWORKS Design & Help

That can be made with the SolidWorks sheet metal features, but it will not flatten. The only way I have made flat-patterns of parts like this is to use surface features. I select all faces on one "side" of the part, use the offset surface feature with a value of 0. Then I hide the body and use the surface flatten feature to get an approximate flat-pattern.

you can make this part using swept blend in PTC Creo or loft feature in Solidworks.

i make this part using swept blend creo which pics below attachment,

I would not consider this as "sheet metal" part, this doesn't look like bent metal but more like stamped part. If you need this part for assembly it is not that hard to model, If you need blank's dimension before stamping it is just a "bar with two washers at the ends" but getting the correct dims and "k" factors will require some experimentations