Thermal stability and buckling analyses of novel encased composite cylinder with polyhedral shapes

Abstract

The present investigation refers mainly to the thermal buckling performance of an encased polyhedral composite cylinder under a varied temperature field. The cylinder is encased rigidly and tightly so that only radially inward deflection occurs. The interface is smooth between the cylinder and encasement. The radius and bending rigidity of the polyhedral cylinder are approximated, so that the classical shell approach may be used. Combining the energy method and an admissible expression to describe the radial displacement, the potential energy function of a polyhedral cylinder is accomplished explicitly. Two equations of equilibrium are developed by taking the first derivative of the energy function. The critical temperature variation is obtained analytically by solving these two equations. Subsequently, a comparison is carried out to verify the accuracy of the present theoretical predictions. The results indicate the present derivation agrees exactly with other closed-form solutions. An improvement factor is defined as the ratio of the critical temperature variation between the polyhedral and circular cylinder. Finally, parametric evaluations show a higher thickness-to-radius ratio, as well as a higher number of sides, may reduce the improvement factor, respectively. Therefore, one may recommend using a polyhedral cylinder with a low thickness-to-radius ratio and small numbers of sides in engineering applications.