how to divide this type of structure in equal parts from bend in solid works pictures attached What is BAS in the picture ?

The easiest way is to create two or more lofted sheet metal parts. I wouldn't do more than four and I would put the splits in the center of the straight edge and those should line up with the quadrants of your top circles. and BAS is a abbreviation used in (HVAC) sheet metal "Bend As Shown" as opposed to BAO "Bend as opposite" most shops now use Bend up or Bend down. Good practice for these transitions are to make them in two pieces and connect them with Pittsburgh joint/seam.