Higher-Order Hierarchical Models for the Free Vibration Analysis of Thin-Walled Beams

Table 3

Dimensionless natural frequencies, box cross section, and .

	Modes I, II	Mode III	Mode IV	Mode V
FEM 3D
FEM 3D
TBT			—	—
EBT		—	—	—

a: cross section mesh. b: cross section mesh.
c: mode not provided by the theory.