Modelling a Cracked Beam Structure Using the Finite Element Displacement Method

Table 4

Comparisons of the first two natural frequencies from the proposed method with 8 × 8 stiffness matrix, the FEFM with 4 × 4 stiffness matrix, and the experimental results for a cracked cantilever beam with open crack.

Crack (mm)		Method	Natural frequency ratio		Difference (%)
X	A		f1/f01	f2/f02	f1/f01	f2/f02
60	2	Experiment	0.977	0.993	—	—
		FEFM	0.992	0.999	1.497	0.587
		Proposed method	0.991	0.999	1.472	0.615
60	5	Experiment	0.919	0.997	—	—
		FEFM	0.961	0.997	4.244	0.012
		Proposed method	0.930	0.997	1.188	0.046
60	7.8	Experiment	0.810	0.960	—	—
		FEFM	0.925	0.994	11.578	3.390
		Proposed method	0.762	0.990	4.804	3.060

FEFM: finite element model with force method.