An actual problem not for brainlets

No.12947103 ViewReplyOriginalReport
Does anyone know how to calculate bucking strength of a U channel beam? I haven't taken enough strengths to do anything beyond rectangular beams or rods. Im working on a capstone project, and it was supposed to be process engineering but here I am designing a fucking RV.
My beams are 1.5 in x 1.5 in with 1/8th wall and a 35 ksi yield strength