Nonlinear Forced Vibration of Bidirectional Functionally Graded Porous Material Beam

Table 1

Verification of the fundamental frequencies of BDFG beam with  h.

	Ref. [30]	2.8330	2.8251	2.8115	2.7919
	Present	2.8332	2.8248	2.8109	2.7918
	Ref. [30]	2.8291	2.8212	2.8076	2.7880
	Present	2.8298	2.8214	2.8076	2.7884
	Ref. [30]	2.8232	2.8154	2.8017	2.7822
	Present	2.8242	2.8158	2.8020	2.7829
	Ref. [30]	2.8154	2.8076	2.7939	2.7744
	Present	2.8163	2.8079	2.7941	2.7751

and are the functional gradient parameters defined in Ref. [30].