Free Vibration Analysis of Rotating Pretwisted Functionally Graded Sandwich Blades

Table 2

Convergence of nondimensional frequency parameters for the first six modes of the FG sandwich blade (, , , , and ).

Mode	ANSYS	5 × 5 × 5		5 × 6 × 6		5 × 7 × 7		5 × 8 × 8		5 × 9 × 9
		Value	Error	Value	Error	Value	Error	Value	Error	Value	Error
1st	4.5272	4.5320	0.11%	4.5209	−0.14%	4.5228	−0.10%	4.5211	−0.13%	4.5215	−0.13%
2nd	27.3966	27.5019	0.38%	27.4741	0.28%	27.4639	0.25%	27.4684	0.26%	27.4665	0.26%
3rd	29.0406	29.5393	1.72%	29.3030	0.90%	29.3432	1.04%	29.2158	0.60%	29.1542	0.39%
4th	76.2376	75.8763	−0.47%	70.8471	−7.07%	74.8356	−1.84%	74.8922	−1.76%	75.0109	−1.61%
5th	80.3331	84.3843	5.04%	78.8139	−1.89%	82.1073	2.21%	82.2715	2.41%	82.2392	2.37%
6th	89.9847	91.5581	1.75%	90.9359	1.06%	91.0424	1.18%	90.7128	0.81%	90.5917	0.67%