Free In-Plane Vibrations of Orthotropic Rectangular Plates by Using an Accurate Solution

Table 1

Essential conditions and stiffness matrixes for different boundary conditions.

Boundary conditions	Corresponding stiffness matrixes (N/m)	Essential conditions
Free (F)		Nxx = Nxy = 0
Clamped (C)
Simply supported 1 (SS1)		Nxx = 0,
Simply supported 2 (SS2)		u = 0, Nxy = 0
Elastic restrained (E)