Research Article

Free Vibration Analysis of the Unified Functionally Graded Shallow Shell with General Boundary Conditions

Figure 4

Variations of the first frequency parameters of the Al/Al2O3 shallow shells with E3E3E3E3 and different material types: Type 1: , ; Type 2: , , ; Type 3: , , ; Type 4: , , .
(a) Plate
(b) Cylindrical shell
(c) Spherical shell
(d) Hyperbolic paraboloidal shell