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The high temperature environment makes the buckling of composite laminated plate happen earlier. Further weight savings can be achieved once the plate has a favorable postbuckling stiffness. This study aims to address this issue by developing a ROM-driven lamination optimization to maximize the buckling and postbuckling performance of compressed plates under initial temperature field. The reduced-order model(ROM) constructed using the improved Koiter theory is reformulated to be suitable for thermal-mechanical buckling problems. A linear subspace of the force space is represented to be the span of the mechanical load, the thermal load and a set of predefined perturbation loads. The thermal load related to the initial temperature field is constant during the increase of in-plane compressive load. An independently additional degree of freedom corresponding to the thermal load is implemented into the construction of the reduced-order model. The buckling and postbuckling performance can be extracted from the solution of reduced-order model, and then subsequently selected as inputs to achieve the optimal laminate. The main novelty of this work is to achieve the thermal-mechanical buckling and postbuckling optimization, benefitting from the highly efficient single run of thermoelastic geometrically nonlinear analysis. Various numerical examples have been selected to validate the performance of the proposed method, considering the influences of length-to-width ratio, α1/α2, ply number and nonuniform temperature field. [ABSTRACT FROM AUTHOR]

Laminated composite cylinders subjected to axial compression exhibit the "snap-back" response, the buckling load of which is very sensitive to initial geometric imperfections. An operating environment with high temperatures influences both the buckling behavior and imperfection sensitivity of thin-walled cylinders. This paper proposes a novel reduced-order modeling method for nonlinear buckling and imperfection sensitivity analyses, considering the effects of the initial geometric imperfections and initial temperature field. The Koiter asymptotic theory is reformulated to construct a thermal–mechanical reduced-order model with initial geometric imperfections. The initial temperature field is converted to an additional degree of freedom during the construction of the reduced-order model. An a posteriori account of geometric imperfections is achieved for the thermomechanical reduced system of the perfect structure. A predictor–corrector process is developed to trace the thermoelastic geometrically nonlinear response of an axially compressed cylinder with geometric imperfections. Various numerical examples are designed to validate the high efficiency and satisfactory accuracy of the proposed method for imperfection sensitivity analyses. The optimization process based on the proposed method is applied to determine the most imperfection-sensitive laminate and the "worst" imperfection shape. • The Koiter perturbation method is extended for the thermal–mechanical buckling of imperfect cylinders. • The initial temperature field is converted to an additional DoF in the reduced-order model. • Geometric imperfections are accounted for a posteriori in the thermomechanical reduced system. • The predictor–corrector process is used to trace the thermoelastic, geometrically nonlinear response. [ABSTRACT FROM AUTHOR]