So First I used the push pull to extend your corregated plates out another 5mm.
Next I created a new ring using your sketch, that extended above and below the corrugations.
after that i combined one of the corregated bodies with the new ring body and selected to Cut the ring body. Repeat with the second corrugated part.
you will now have 3 bodies where once you had a ring.
Ive attached your model with the 3 bodies still present.
last I created a wider circle in sketch and extruded that to cut off the excess corrugated material. there is a little strangeness at the outside edge.
In the future, you may want to create your corrugation profile sketch somewhat larger than the final design, then you could use it repetedly to cut and parts such as the outer ring.
