Fig. 14.
Panel a shows secant stiffness at cycle 0, K 0, in meganewtons per metre against zeta b. Zeta b ranges from 0.3 to 1.0 and K 0 ranges from 0 to 25 meganewtons per metre. Present study values near zeta b 0.5 range from about 19 to 23 meganewtons per metre, while values near zeta b 0.85 range from about 7 to 13 meganewtons per metre. Equation 11 decreases from about 25 meganewtons per metre at zeta b 0.4 to about 9 meganewtons per metre near 0.9. Li et al. 2022 decreases gradually from about 5 to 2 meganewtons per metre. Panel b shows secant stiffness at cycle 1, K 1, against secant stiffness at cycle 0, K 0, in meganewtons per metre. K 0 ranges from 0 to 35 meganewtons per metre and K 1 ranges from 0 to 50 meganewtons per metre. Present study values increase from about 19 to 40 meganewtons per metre with increasing K 0. Equation 12 increases nonlinearly from 0 to about 45 meganewtons per metre.Secant stiffnesses relationships between: (a) K0 and ΞΆb and (b) K1 and K0