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

Table 2

Fitting coefficients for the nonlinear relationship between the 1st-order damping ratio and amplitude.

Algorithm	Condition	Coefficient					R^2
		a	b	c	d	e
POD (svd)	Air	0.0488	0.0292	−0.00326	6.782E − 04	0.00401	0.997
LogDec		0.0496	0.0305	−0.00360	7.459E − 04	0.00415	0.999
POD (svd)	Still water	0.0431	0.0351	−0.00276	5.884E − 04	2.360E − 03	0.997
LogDec		0.0463	0.0365	−0.00280	1.347E − 04	1.858E − 04	0.993