# 4.13.5.26. BoucWen Material¶

uniaxialMaterial('BoucWen', matTag, alpha, ko, n, gamma, beta, Ao, deltaA, deltaNu, deltaEta)

This command is used to construct a uniaxial Bouc-Wen smooth hysteretic material object. This material model is an extension of the original Bouc-Wen model that includes stiffness and strength degradation (Baber and Noori (1985)).

 matTag (int) integer tag identifying material alpha (float) ratio of post-yield stiffness to the initial elastic stiffenss (0< alpha <1) ko (float) initial elastic stiffness n (float) parameter that controls transition from linear to nonlinear range (as n increases the transition becomes sharper; n is usually grater or equal to 1) gamma beta (float) parameters that control shape of hysteresis loop; depending on the values of gamma and beta softening, hardening or quasi-linearity can be simulated (look at the NOTES) Ao deltaA (float) parameters that control tangent stiffness deltaNu deltaEta (float) parameters that control material degradation