Multilayer heterostructure inhomogeneous model for pressurized functionally graded annular structures (cylinder/sphere/annulus) with arbitrary elastic property along the radial direction

•A natural and highly accurate multilayer heterostructure inhomogeneous model.•The pressurized FGMs annular structures of cylinder, sphere or annulus.•The FGMs with arbitrary elastic properties along the radial direction.•Hundreds of numerical examples proving the reliability of the method.•Avoidance of circumferential stress oscillation in multilayer homogeneous model.•Application of this multilayer inhomogeneous model to other complex problems.