Well, I'm confused. Your 3D object is listed as a single Polyline under the Selection Info panel.
I traced the inside curve of the narrow face, then Offset it and added two short lines to connect the two pieces together followed by a Simple Extrude to duplicate your structure. After I Exploded it to get an ACIS Solid, I tried Unbend Sheet, which only partially succeeded (the top facet on the outside curve, shown in blue, and the second flat section on the inside curve, starting from the other end, shown in red).
TC Pro Platinum 2019, 2018, 2017, 2016 & 2015 (all with LightWorks & RedSDK) & V21
System: i7-5820K @ 3.30GHz, ASRock X99 Extreme4, 16GB DDR4-2133 RAM, Gigabyte GTX 970, Samsung NVMe SSD 950 (256GB), Windows 7 Pro (64-bit) SP1