Multi-Factor Modeling Method of the Load Sharing Ratio under Moving Train Loads

Table 4

Factor level coding.

Test factor level	Zero level (0)	Variation range (∆)	Upper level (+1)	Lower level (−1)	Upper asterisk arm (+1.078)	Lower asterisk arm (−1.078)
kf (MN·m^−1)	35	13.91	48.91	21.09	50	20
a (m)	0.575	0.07	0.64	0.51	0.65	0.5