A New Experimental Method for the Nonlinear Modal Parameter Identification of a Pressurized Water Reactor Fuel Assembly

Table 1

Fitting coefficients for the nonlinear relationship between the 1st-order natural frequency and amplitude.

Algorithm	Condition	Coefficient					R^2
		a	b	c	d	e
POD (svd)	Air	3.956	−0.567	0.180	0.057	0.026	0.999
LogDec		3.855	−0.445	0.110	0.032	0.015	0.998
POD (svd)	Still water	3.462	−0.149	0.008	−1.311E − 04	−1.439E − 05	0.999
LogDec		3.525	−0.297	0.069	1.749E − 02	8.120E − 03	0.995