Use when you must compute the local crippling and inter-rivet allowables of a formed compression stiffener (angle, channel, Z, hat stringer, bulb angle): compute the element crippling stress F_cc = min(F_cy, C*sqrt(F_cy*E)*(t/b)**0.75) with the shape constants C = 0.31 for one-edge-free flanges and C = 0.55 for webs between corners, average the element crippling loads over the section area, compute the inter-rivet buckling stress of the attached flat from the rivet pitch, and run the Johnson-Euler interaction that anchors the stiffener column curve on the local crippling stress.
