Rp. Ley et al., OPTIMAL-DESIGN OF IMPERFECT, ANISOTROPIC, RING-STIFFENED CYLINDERS UNDER COMBINED LOADS, Structural optimization, 9(3-4), 1995, pp. 160-167
Development of an algorithm to perform the optimal sizing of buckling
resistant, imperfect, anisotropic ring-stiffened cylinders subjected t
o axial compression, torsion, and internal pressure is presented. An a
xisymmetric, geometrically nonlinear prebuckling equilibrium configura
tion is assumed and both stress and stability constraints are consider
ed. The enforcement of stability constraints is treated in a way that
does not require any eigenvalue analysis. Case studies performed using
a combination of penalty function and feasible direction optimization
methods indicate that the presence of the axisymmetric initial imperf
ection in the cylinder wall can significantly affect the optimal desig
ns. Weight savings associated with the addition of two rings to the un
stiffened cylinder and/or the addition of internal pressure is substan
tial when torsion makes up a significant fraction of the combined load
state.