Effects of parameter uncertainties on the forecasted behavior of thermomechanically loaded thick-walled functionally graded spherical structures

The subject of the investigation is an elastic functionally graded hollow spherical device under internal pressure and homogeneous heating. Since in reality uncertain parameter values are to be expected with respect to both basic material data and influences of the manufacturing process, the effects of these uncertainties are in the focus of the present study. For the numerical results, specifically a container or pressure vessel of steel-aluminum functionally graded material is considered. Essentially, the largest possibly occurring von Mises stress is taken as an assessment criterion. It is demonstrated that uncertainty ranges of the system inputs may cause much larger scattering ranges (in percentages) of the predicted maximum stresses. Moreover, the sensitivity of the results to variations of different individual parameter values is discussed, and it is shown that an application of sophisticated and computationally expensive homogenization schemes to the functionally graded material is meaningful only if the basic data can be determined with quite high accuracy.