An efficient method to improve the stability of submerged functionally graded cylindrical shell

An efficient method is presented to improve the stability of a submerged functionally graded (FG) cylindrical shell which is subjected to external hydrostatic pressure. To improve stability while satisfying the application requirements for shell thickness, we focused on the optimum value of the power-law exponent to maximize the critical hydrostatic pressure. The optimum value of the power-law exponent is obtained from an analysis of the influence factors on critical pressure. The results show that the critical pressure can be greatly increased by using the optimum value of the power-law exponent, and the growth rate of critical pressure is almost constant independent of the shell geometry and boundary condition. The advantage of the present method in reducing the shell thickness is illustrated by examples. In addition, the present method is applicable to all kinds of material combinations.