Hybrid uncertainty analysis of functionally graded plates via multiple-imprecise-random-field modelling of uncertain material properties

Abstract This paper presents the mixed probabilistic/non-probabilistic uncertainty problem regarding the hybrid uncertainty propagation on physical model of functionally graded plates through dissimilarly uncertain characterisation of material properties in the presence of the multiple-imprecise-random-field modelling. The spectral stochastic finite element framework is extended to perform mixed uncertainty analysis of functionally graded material whereby the spatial variation of elastic modulus of the plate is uniquely characterised as the multiple-imprecise-random-field modelling more than a purely homogeneous random field. This characterisation has originated in heeding the construction of physical models and the significant influences of separately uncertain characteristics propagated on the physical model through different material ingredients are examined to make physical models more reliable and realistic. Mechanics and mathematics intrusive-formulations are then established to explicitly produce the uncertain-but-bounded statistical characteristics of responses, namely interval mean value, interval standard deviation. Bounded surfaces of statistical moments and bounding distribution functions are vividly depicted for demonstration. The feasibility and effectiveness of the presented work are illustrated via test cases of numerical examples.