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

Table 21

% of the relative errors on the variance of the critical speeds for different regression orders and correlation functions. Symmetric case with 70 samples.

	Gaussian	Linear	Exponential	Cubic
Zero-order regression
	(96.76; 2.37)	(332.46; 17.27)	(263.73; 10.69)	(385.09; 30.54)
	(27.88; 2.20)	(60.14; 4.62)	(21.53; 2.98)	(123.27; 8.79)
	(9.67; 1.42)	(10.34; 1.72)	(12.46; 1.69)	(8.62; 2.25)
	(9.64; 1.48)	(20.13; 2.36)	(16.51; 2.23)	(22.65; 3.41)
	(1.53; 0.15)	(3.57; 0.40)	(3.03; 0.27)	(3.88; 0.77)
	(0.65; 0.04)	(9.00; 0.74)	(2.91; 0.28)	(12.33; 1.72)
	(0.93; 0.02)	(3.51; 0.34)	(3.00; 0.16)	(4.70; 0.70)
	(0.14; 0.00)	(1.74; 0.13)	(0.48; 0.05)	(2.44; 0.30)
First-order regression
	(66.48; 2.41)	(129.92; 4.29)	(111.42; 4.00)	(144.74; 6.25)
	(20.73; 2.02)	(14.25; 2.07)	(11.62; 2.13)	(16.73; 2.59)
	(8.20; 1.41)	(10.79; 1.79)	(11.90; 1.77)	(11.52; 2.37)
	(8.48; 1.44)	(6.97; 1.49)	(7.41; 1.59)	(8.08; 1.67)
	(0.89; 0.15)	(3.24; 0.20)	(2.98; 0.19)	(3.70; 0.27)
	(0.98; 0.03)	(3.50; 0.13)	(3.20; 0.13)	(3.93; 0.20)
	(0.45; 0.01)	(1.65; 0.07)	(1.45; 0.07)	(1.87; 0.12)
	(0.02; 0.00)	(0.07; 0.00)	(0.07; 0.00)	(0.09; 0.01)
Second-order regression
	(30.99; 1.92)	(76.33; 2.81)	(64.43; 2.70)	(88.36; 3.59)
	(10.01; 1.71)	(13.87; 1.93)	(13.16; 2.02)	(13.19; 1.99)
	(4.87; 1.36)	(11.05; 1.59)	(9.26; 1.58)	(14.01; 1.77)
	(6.08; 1.38)	(8.91; 1.42)	(9.05; 1.51)	(9.09; 1.51)
	(0.77; 0.14)	(1.33; 0.16)	(1.30; 0.16)	(1.63; 0.17)
	(0.15; 0.02)	(0.55; 0.03)	(0.53; 0.04)	(0.68; 0.05)
	(0.04; 0.01)	(0.14; 0.01)	(0.13; 0.01)	(0.16; 0.01)
	(0.00; 0.00)	(0.01; 0.00)	(0.01; 0.00)	(0.02; 0.00)