1-5 Material model real constant number (N) 6-15 Stiffness factor 1 (K1) 16-25 Stiffness factor 2 (K2) 26-35 Stiffness factor 3 (K3) 36-45 Stiffness factor 4 (K4) 46-55 Stiffness factor 5 (K5) 56-65 Stiffness factor 6 (K6)