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

Table 3

Analysis of variance for complex viscosity.

Source	Sum of squares	df	Mean square	F value	value
Model	6698.75	20	334.94	0.6485	0.8414	Significant
A (load frequency)	57.90	1	57.90	0.1121	0.7402
B (% of STF with oil)	27.69	1	27.69	0.0536	0.8185
C (initial viscosity)	0.2347	1	0.2347	0.0005	0.9831
D (stiffener thickness)	2.20	1	2.20	0.0043	0.9485
E (applied force)	389.73	1	389.73	0.7546	0.3922
AB	6.90	1	6.90	0.0134	0.9088
AC	253.91	1	253.91	0.4916	0.4888
AD	663.75	1	663.75	1.29	0.2662
AE	15.88	1	15.88	0.0307	0.8620
BC	1095.82	1	1095.82	2.12	0.1560
BD	92.28	1	92.28	0.1787	0.6756
BE	257.30	1	257.30	0.4982	0.4859
CD	114.53	1	114.53	0.2218	0.6412
CE	205.34	1	205.34	0.3976	0.5333
DE	847.28	1	847.28	1.64	0.2104
A^2	122.77	1	122.77	0.2377	0.6295
B^2	483.81	1	483.81	0.9367	0.3411
C^2	1658.96	1	1658.96	3.21	0.0835
D^2	50.48	1	50.48	0.0977	0.7568
E^2	26.98	1	26.98	0.0522	0.8208
Residual	14978.40	29	516.50
Lack of fit	11524.94	22	523.86	1.06	0.5046	Not significant
Pure error	3453.46	7	493.35
Cor total	21677.15	49