Natural frequency of bi-stable composite plates in thermal environments

The natural frequency of bi-stable cross-ply [0n/90n]_T composite plates under thermomechanical loading is analysed theoretically. Based on Hamilton's principle, in conjunction with the Rayleigh-Ritz method, the analytical model with only 17 unknown terms is applied to predict the natural frequency of bi-stable composite plates. The properties of the composite material in current study are considered to be functions of temperature. The plate is subjected to two different thermal load, i.e. the uniform temperature field and through-thickness thermal gradient. The influence of this two temperature field on the natural frequency of the thin composite plates is predicted theoretically. Moreover, the predicted results are greatly affected by the uncertainty of uncertainties in geometry, material properties and the operating environment. The considered uncertainties include Young's moduli, Poisson's ratio and shear modulus, thermal expansion coefficients, ply thickness, density, cure and ambient temperature. The thermal effect and sensitivity to uncertainties are of great importance to the design and application of morphing structures manufactured from bi-stable composite plates.