There's an old article that we used one time for the lug forces & moments going into the shell. P.Seide, "On the Bending of Circular Cylindrical Shells by Equal & Equally Spaced End Radial Shear Forces & Moments," Trans. ASME, Jnl Applied Mech., March 1961, pp.117-126. Get equivalent uniform loadings, then use beam-on-elastic-foundation eq's from Roark. Kinda painful the first time through, but not bad if you put it into mathCAD.