Optimal Evaluation of the Rheological Parameters for STF Dampers in Semi-Rigid Joints of Steel Structures Using Response Surface Method

Table 5

ANOVA for effective stiffness.

Source	Sum of squares	df	Mean square	F value	value
Model	86492.70	20	4324.63	0.6716	0.8209	Significant
A (load frequency)	12738.61	1	12738.61	1.98	0.1702
B (% of STF with oil)	6.25	1	6.25	0.0010	0.9754
C (initial viscosity)	1607.23	1	1607.23	0.2496	0.6211
D (stiffener thickness)	7427.21	1	7427.21	1.15	0.2917
E (applied force)	5564.66	1	5564.66	0.8641	0.3603
AB	6469.53	1	6469.53	1.00	0.3245
AC	3154.17	1	3154.17	0.4898	0.4896
AD	3764.95	1	3764.95	0.5847	0.4507
AE	6707.72	1	6707.72	1.04	0.3159
BC	441.05	1	441.05	0.0685	0.7954
BD	403.28	1	403.28	0.0626	0.8042
BE	2471.05	1	2471.05	0.3837	0.5405
CD	843.58	1	843.58	0.1310	0.7200
CE	4687.54	1	4687.54	0.7279	0.4005
DE	4491.15	1	4491.15	0.6974	0.4105
A^2	2437.84	1	2437.84	0.3786	0.5432
B^2	1921.93	1	1921.93	0.2985	0.5890
C^2	13457.42	1	13457.42	2.09	0.1590
D^2	1935.10	1	1935.10	0.3005	0.5878
E^2	2596.50	1	2596.50	0.4032	0.5304
Residual	1.867E + 05	29	6439.62
Lack of fit	1.354E + 05	22	6152.28	0.8379	0.6531	Not significant
Pure error	51398.95	7	7342.71
Cor total	2.732E + 05	49