Design and thermo-mechanical analysis of sandwich structures with negative thermal expansion

In this study, an analytical model based on Classic Laminate Theory was developed for the prediction of effective thermal expansion coefficients (ETECs) of general angle-ply laminates (symmetrical and asymmetrical). Examples are given of the applications of the analytical solution to the prediction of the ETEC of sandwich structures with fiber reinforced composite (FRC) core for various ply angles. The proposed analytical solutions are applied to predict the ETEC of laminate structures with fiber reinforced composite core for various ply angles. Laminate structures with negative thermal expansion (NTE) are obtained and considered as special cases of interest. For an extreme case, a laying angle of [0_Ti/(± 30)_2S/0_Ti] and [0_Ti/(± 60)_2S/0_Ti] along with an NTE of -1.335 × 10^–5/K has been achieved. Meanwhile, Finite Strip Method is extended to the framework of first order shear theory, and the corresponding governing equations are established. With the help of the Bolotin method, the dynamic instability region of the sandwich structures with NTE is obtained. Numerical results show that the thermal vibration, buckling and dynamic instability behaviors may be adjusted and controlled by changing the TEC and stacking configurations. The present analytical results are not only theoretical fundament for understanding the interrelationship between the mechanical and temperature dependent material properties and the shrinkage of the structures but also serve as guiding NTE design of structures.