Investigation of thermo-elasto-plastic behavior of thick-walled spherical vessels with inner functionally graded coatings

Having high corrosion and thermal resistance characteristics, Functionally Graded Materials have been found wide range of applications in engineering fields. The analytical elasto-plastic solution for spherical vessels composed of outer homogenous part and inner FG coating under combined pressure and thermal loading is presented in this paper. Furthermore, the loading conditions resulted into onset of yielding from inner radius and fully plastic vessel are obtained. Material constituents in both homogenous and FG parts are assumed to be aluminum and SiC as metal matrix and ceramic particles, respectively. Although the amount of SiC particles in the homogenous part of vessel is assumed to be constant, it is varying in the radial direction of FG part based on the power law function. The results concerning two types of vessels with harder and softer FG coatings are also compared with those from homogenous vessel. Moreover, two dimensional finite element model was applied to simulate the process while the results were considered to verify the accuracy of the analytical solution. Generally, the results demonstrate that coating and grading behavior can really affect the stress distribution and yield pattern in the homogenous vessel with an inner FG coating.