Optimization of Elastic, Multilayer, Cylindrical Vessels Loaded by Pressure and Radial Thermal Gradient

Radius and interference design parameters of elastic, multilayer, thick-walled cylindrical vessels are optimized on the basis of the Mises distortion energy yield criterion. Loadings are assumed uniform along cylinder length and may be independently applied or combined internal pressure and steady-state axiallysymmetric thermal gradients, as well as specified initial stresses to simulate autofrettage or other residual stresses. The optimization is effected by an accelerated, steepest-ascent, gradient projection method, subjected to constraints on loaded stress intensity, shrink stress intensity, end loading, tangential stress (e.g., for a brittle liner), and monotonic-decreasing interface pressures. Independent elastic and thermal properties are allowed for each layer; however, time-dependent phenomena are not considered. The general procedure developed is compared with several published optimization solutions for various special cases.