Thermal-mechanical Buckling Analysis and Optimization of the Stringer Stiffened Cylinder Using Smeared Stiffener Based Reduced-Order Models.

In this work, the thermal-mechanical buckling analysis and optimization of stringer stiffened cylindrical shells are achieved using the smeared stiffener based reduced-order models. A novel reduced-order modeling method is proposed for nonlinear buckling analysis of the stringer stiffened cylinder subjected to an axially compressive load and initial temperature field. The reduced-order model is constructed based on the improved Koiter perturbation theory and the smeared stiffener method. The axially compressive load, initial temperature field and perturbation loads are converted to be the degrees of freedom in the smeared stiffener based reduced-order model. The thermoelastic geometrically nonlinear response of the stringer stiffened cylinder can be obtained using the proposed method accurately and efficiently. Optimization problems are designed to achieve the optimal stiffening configuration for minimum weight and maximum buckling load, where the solutions of reduced-order models are selected as inputs. Stringer stiffened cylinders with various ratios of radius to thickness and length to radius are considered to illustrate the good performance of the proposed method. Compared to the fully nonlinear analysis based on the classical finite element method, the proposed method can achieve the nonlinear buckling load of the stringer stiffened cylinder much more efficiently and realize the optimization of the stiffening configuration at an affordable computational cost.