Kriging Metamodeling in Rotordynamics: Application for Predicting Critical Speeds and Vibrations of a Flexible Rotor

Table 5

% of the relative errors of the mean of critical speeds for different regression orders and correlation functions. Nonsymmetric case with 600 samples.

	Gaussian	Linear	Exponential	Cubic
Zero-order regression
	(17.86; 0.29)	(28.58; 0.65)	(25.30; 0.36)	(40.20; 0.81)
	(10.94; 0.10)	(10.33; 0.14)	(12.82; 0.11)	(8.58; 0.10)
	(2.55; 0.02)	(4.54; 0.16)	(3.02; 0.08)	(10.40; 0.27)
	(3.37; 0.02)	(4.07; 0.08)	(0.99; 0.03)	(11.01; 0.14)
	(0.00; 0.00)	(2.04; 0.06)	(0.66; 0.02)	(4.65; 0.11)
	(0.00; 0.00)	(2.22; 0.05)	(0.74; 0.02)	(5.15; 0.10)
	(0.00; 0.00)	(0.54; 0.01)	(0.18; 0.00)	(1.23; 0.03)
	(0.00; 0.00)	(0.31; 0.01)	(0.10; 0.00)	(0.70; 0.02)
First-order regression
	(11.98; 0.25)	(23.81; 0.50)	(23.13; 0.30)	(27.46; 0.56)
	(6.51; 0.09)	(12.64; 0.15)	(14.28; 0.12)	(7.42; 0.08)
	(1.54; 0.02)	(1.93; 0.07)	(2.04; 0.04)	(3.66; 0.10)
	(0.86; 0.01)	(1.33; 0.04)	(1.59; 0.03)	(1.69; 0.03)
	(0.00; 0.00)	(0.39; 0.01)	(0.27; 0.00)	(0.70; 0.01)
	(0.00; 0.00)	(0.11; 0.00)	(0.07; 0.00)	(0.26; 0.01)
	(0.00; 0.00)	(0.05; 0.00)	(0.04; 0.00)	(0.10; 0.00)
	(0.00; 0.00)	(0.01; 0.00)	(0.00; 0.00)	(0.01; 0.00)
Second-order regression
	(8.98; 0.20)	(20.97; 0.38)	(21.40; 0.24)	(16.80; 0.35)
	(6.35; 0.08)	(12.26; 0.14)	(13.91; 0.12)	(8.45; 0.08)
	(0.63; 0.01)	(1.22; 0.04)	(1.57; 0.03)	(1.11; 0.03)
	(0.60; 0.01)	(1.20; 0.03)	(1.43; 0.02)	(1.14; 0.02)
	(0.00; 0.00)	(0.07; 0.00)	(0.06; 0.00)	(0.11; 0.00)
	(0.00; 0.00)	(0.05; 0.00)	(0.04; 0.00)	(0.10; 0.00)
	(0.00; 0.00)	(0.00; 0.00)	(0.00; 0.00)	(0.00; 0.00)
	(0.00; 0.00)	(0.00; 0.00)	(0.00; 0.00)	(0.00; 0.00)