.. function:: uniaxialMaterial('BWBN', matTag,alpha, ko, n, gamma, beta, Ao, q, zetas, p, Shi, deltaShi, lambda, tol, maxIter)
:noindex:
This command is used to construct a uniaxial Bouc-Wen pinching hysteretic material object. This material model is an extension of the original Bouc-Wen model that includes pinching (Baber and Noori (1986) and Foliente (1995)).
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``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 BoucWen Material)
``Ao`` |float| parameter that controls tangent stiffness
``q`` ``zetas`` ``p`` ``Shi`` ``deltaShi`` ``lambda`` |float| parameters that control pinching
``tol`` |float| tolerance
``maxIter`` |float| maximum iterations
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.. seealso::
`Notes <http://opensees.berkeley.edu/wiki/index.php/BWBN_Material>`_