The thermal loads include the uniform temperature rise and nonlinear temperature change across the thickness of shell. A closed form solution for the thermal buckling of simply supported cylindrical FG shell under the described thermal loads is obtained. The influences of the relative thickness, the imperfection size and the power law index on buckling thermal loads are all discussed. | Vietnam Journal of Mechanics, VAST, Vol. 30, No. 3 (2008), pp. 185 – 194 THERMAL BUCKLING OF IMPERFECT FUNCTIONALLY GRADED CYLINDRICAL SHELLS ACCORDING TO WAN-DONNELL MODEL Hoang Van Tung Hanoi Architectural University, Vietnam Nguyen Dinh Duc Vietnam National University, Hanoi Abstract. A thermal buckling analysis of imperfect circular cylindrical shells of functionally graded material is considered. The material properties are assumed varying as a power form of thickness coordinate variable. The Donnell equilibrium and stability equations are considered and the Wan-Donnell model for initial geometrical imperfection is adopted. The thermal loads include the uniform temperature rise and nonlinear temperature change across the thickness of shell. A closed form solution for the thermal buckling of simply supported cylindrical FG shell under the described thermal loads is obtained. The influences of the relative thickness, the imperfection size and the power law index on buckling thermal loads are all discussed. 1. INTRODUCTION The initial geometric imperfections are inherent in many real structures. Therefore, many investigations are conducted on the stability analysis of imperfect structures. Elastic, plastic, and creep buckling of imperfect cylinders under mechanical and thermal loads is studied by Eslami and Shariyat [3]. Mossavarali et al. studied the thermoelastic buckling of isotropic and orthotropic plates with imperfections [8, 9]. Murphy and Ferreira [10] investigated thermal buckling analysis of clamped rectangular plates based on the energy consideration. They determined the ratio of the critical temperature for a perfect flat plate to that one for an imperfect plate as a function of the initial imperfection size. The study includes experimental results. Eslami and Shahsiah [2] reported thermal buckling of imperfect circular cylindrical shells made of isotropic materials. They used the WanDonnell and Koiter models to describle initial geometrical .
