Coupled thermo-mechanical analysis of one-layered and multilayered isotropic and composite shells

Abstract

This work considers the fully coupled thermo-mechanical analysis of one-layered and multilayered isotropic and composite shells. The temperature is assumed a primary variable as the displacement; it is therefore directly obtained from the model and this feature permits the temperature field to be evaluated through the thickness direction. Three problems are analyzed: - static analysis of shells with imposed temperature on the external surfaces; - static analysis of shells subjected to a mechanical load, with the possibility of considering the temperature field effects; - a free vibration problem, with the evaluation of the temperature field effects. In the first problem, imposing a temperature at the top and bottom of the shells, the static response is given in terms of displacements, stresses and temperature field; the proposed method is very promising if compared to a partially coupled thermo-mechanical analysis, where the temperature is only considered as an external load, and the temperature profile must be a priori defined (considering it linear through the thickness direction or calculating it by solving the Fourier heat conduction equation). A mechanical load is applied in the second problem. The fully coupled thermo-mechanical analysis gives smaller displacement values than those obtained with the pure mechanical analysis; the temperature effect is not considered in this latter approach. The third problem is the free vibration analysis of shells. The fully coupled thermo-mechanical models permit the effect of the temperature field to be evaluated: larger frequencies are obtained with respect to the pure mechanical models. Several refined theories with orders of expansion in the thickness direction, for displacements and temperature, from linear to fourth-order are obtained in the framework of Carrera's Unified Formulation. Both equivalent single layer and layer wise approaches are considered for the multilayered shells.