Parametric Study on the Influence of Warping Deformation upon Natural Frequencies of Die Springs

Table 6

Change law of the warping effect on natural frequencies with respect to the helix pitch angle.

Mode number (Hz)		1	2	3	4	5
	FEM	533.77	966.74	980.62	993.31	1120.5
	Warping ignored	748.56	1082.97	1099.23	1137.02	1345.44
	Error (%)	40.24	12.02	12.09	14.47	20.07
	Warping included	525.88	957.13	971.50	978.46	1112.27
	Error (%)	1.50	0.99	0.93	1.49	0. 73
	FEM	528.43	840.48	862.36	981.13	1125.3
	Warping ignored	740.62	936.78	973.11	1122.27	1330.55
	Error (%)	40.15	11.46	12.84	14.39	18.24
	Warping included	521.71	834.46	855.53	970.49	1119.82
	Error (%)	1.27	0.72	0.79	1.08	0.49
	FEM	520.35	722.19	751.51	966.25	1118.0
	Warping ignored	722.42	809.66	856.58	1119.07	1307.31
	Error (%)	38.83	12.11	13.95	15.82	16.93
	Warping included	515.27	718.51	747.84	957.19	1115.40
	Error (%)	0.97	0.51	0.51	0.94	0.23
	FEM	509.13	625.76	663.87	949.78	1106.1
	Warping ignored	676.70	703.33	787.78	1113.24	1273.52
	Error (%)	32.91	12.40	18.66	17.21	15.14
	Warping included	504.25	622.41	659.50	941.67	1102.38
	Error (%)	0.96	0.54	0.66	0.85	0.34