<p>Thermal fluctuations significantly impact the frequencies and loss factors of structures with viscoelastic layers. These fluctuations change material properties, induce stresses, and, when combined with initial curvature, amplify deformations and further modify modal properties due to temperature changes. This study investigates these effects, focusing on how temperature and imperfections affect through-thickness strain distributions in mode shapes. A higher-order theory, accounting for thickness deformation, is used to model the viscoelastic core. The finite element method is employed to discretize the problem. Quintic Hermite interpolation functions are used to approximate the imperfection function between nodes, enabling efficient integration. The pre-stress and pre-deformations from steady-state temperature increases are estimated using the Newton–Raphson method to solve the nonlinear thermo-elastic equilibrium equations. The natural frequencies and loss factors are then determined by solving the oscillatory equations linearized around the equilibrium state. Numerical analyses provide novel and insightful findings regarding the effects of temperature rise and imperfection on the loss factor and frequency. Specifically, the study investigates temperature effects up to the buckling point, considering two potential buckling modes: global and wrinkling-like. Contour plots of through-thickness normal and shear strains in the core reveal substantial distribution changes influenced by temperature rise and curvature amplitude. Additionally, boundary conditions with the upper layer’s edge left unconstrained are analyzed, demonstrating enhanced damping due to increased through-thickness normal strain within the core.</p>