Free Vibration Analysis of Arbitrary-Shaped Plates Based on the Improved Rayleigh–Ritz Method

Table 13

Natural frequencies of the isosceles trapezoidal plate under the simply supported boundary condition (S-S-S-S) (Hz).

Mode	Simply supported
	Present	FEM	Error (%)
1	1.34	1.33	0.70
2	3.15	3.14	0.35
3	3.70	3.69	0.33
4	5.70	5.68	0.36
5	6.06	6.05	0.17
6	7.52	7.51	0.22
7	9.09	9.07	0.19
8	9.58	9.56	0.20
9	9.97	9.96	0.16
10	12.56	12.55	0.06